THE MENU; Eggs in Eggs in Aspic; With Herb Sauce; Beef Birds in Fried Potato Nests; Asparagus Tips in Sheaves; April Food

THIS April Fool's Day dinner consists of delicious foods in the guise of feeble jokes. It starts with seemingly whole eggs in aspic sitting innocently in a ring of egg yolks parsley. But when the eggs are cut, red salmon caviar spills out from the cavities. A palegreen herb adds sparkle.

The main course is a quasi-sylvan still life: Braised beef birds perch in crispy brown nests of grated potatoes fried in a special tool, with the scene completed by little thickets of lightly buttered asparagus tips tied into sheaves with blanched strands of scallion. The meal ends fittingly with a frivolous (English) April fool.

The aspic is made by cooking a turgid mixture of chicken broth, tomato juice, gelatin, seasonings and lightly beaten egg whites and then passing it through a strainer lined with wrung-out cheesecloth. The miracle occurs when the crystal-clear amber aspic drips through the strainer, leaving behind a miserable-looking mass of particles. Aspic can be made at least a day in advance, refrigerated, reliquified over heat and cooled to room temperature before it is used.

The eggs are hard-cooked rather than poached, as they are traditionally for eggs in aspic, which simplifies matters considerably. The addition of a little aspic thickens the red caviar and makes it easier to put the halves together without losing the filling. The eggs are placed in the molds uncut side down and thus appear to be intact when they are unmolded. Little oval metal molds made especially for eggs in aspic can be found in good kitchenware stores, but ordinary custard cups work perfectly well. The eggs can be assembled the day before or the morning of the dinner.

If thinly sliced boneless round steaks, which are needed for the beef birds, are not to be found already packaged in supermarket cases, ring the service bell and ask for them. I use the food processor to grind the pork for the filling. The beef birds consist of 4-by-5-inch pieces of thin round steaks spread with the ground pork mixture. Should the steaks not cut into perfect rectangles, begin rolling the uneven end first so that the final roll nevertheless measures 4 inches long.

The potato nest maker, which comes in three sizes, is sold by most kitchenware stores, although prices vary, so it pays to shop by telephone. The tool consists of two tinned steel wire baskets attached to handles. The larger basket appropriate for main courses measures 4 3/4 inches in diameter at the top. This is packed with a layer of grated potatoes. The smaller basket, whose diameter is 4 inches, fits into the larger one and molds the potatoes into shape. The two baskets are fastened with clips that attach to the handles. The handles are 17-inches long so the cook can stand back when the baskets are lowered into the hot oil, which at first boils up with fury no matter how well the potatoes have been dried. Fortunately, the cauldron subsides quickly.

These nests are made one at a time. They are more easily released from the baskets after they are half-cooked to a pale brown rather than when they are completely done. The nest maker is removed from the oil and set on a paper-towel-lind jellyroll pan while a dinner knife is run over the wires to loosen the nest. Then the freed nest is returned to the oil with tongs and cooked to a deep brown. The nests can be made earlier in the day and left to drain on the paper towels. In the unlikely case they lose their crispness, they can be placed in a moderate oven for a few minutes before they are filled.

The asparagus tips are cooked for a few minutes just before they are served. I blanch a few extra scallion strands in case some of them break when the sheaves are tied. This can be done in advance or in the asparagus water just before the tips go in. Asparagus stalks can be used for soup. Discard the white, woody ends, cut the stalks into 1/2-inch pieces and cook in water until they are very soft. Drain well and puree in the processor. Then saute' some minced onion in butter until soft, add chicken broth, the pureed asparagus, a little cream, a bit of milk, salt and pepper. The soup is good hot or cold.

The dinner plates are composed in the kitchen. Place a nest on each plate. Then remove the strings from the beef birds and cut each bird in half. Arrange three of the halves cut-side down in each nest and spoon some of the sauce with its vegetables over them. Tie the asparagus tips and stand one sheaf upright on each plate.

The April fool is an uncomplicated concoction of frozen raspberry pure'e, beaten egg whites, whipped cream and some of the raspberry juice. The pure'e can be made the day before, but the fool, which is put together in no time, should not be assembled more than four hours before serving. It can be refrigerated and then brought to room temperature. The fool also can be made with fresh strawberries, but rather than pure'eing the fruit, mash it with a fork since the flavor is better when the berries retain a little body. EGGS IN EGGS IN ASPIC (8 servings) 3 cups canned chicken broth 1 cup tomato juice 4 envelopes unflavored gelatin 1 teaspoon sugar Salt and pepper to taste 2 egg whites, lightly beaten 2 tablespoons cognac For the filling: 4-ounce jar red salmon caviar 2 tablespoons of the aspic For assembling the eggs: 8 hard-cooked eggs The remaining aspic The reserved yolks of the eggs 1 cup minced parsley

To make the aspic, combine the chicken broth, tomato juice, gelatin, sugar, salt, pepper and lightly beaten egg whites in a saucepan. Place over low heat and, stirring constantly, bring to the boil. Ladle the mixture through a strainer lined with wrung-out cheesecloth. Discard residue remaining in the cheesecloth. Stir the cognac into the clear aspic and set aside.

When the aspic is cool but still liquid, spoon a thin layer into eight egg molds or custard cups and refrigerate.

Empty the red salmon caviar into a bowl, stir in 2 tablespoons of the aspic to thicken the caviar and refrigerate.

To assemble the eggs, slice them in half lengthwise. Remove the yolks and reserve them. Place the halves on a plate side by side, marking the beginning with, for example, a plastic bag tie, so that each half can be matched later with its mate.

Fill each hollow of the whites with the caviar mixture and paint a bit of aspic on the cut surfaces of the eggs. Fit each pair of filled whites together and place the eggs in the molds or custard cups with the uncut sides facing bottom and top. Spoon the remaining aspic into the molds and refrigerate until set. The eggs can be made the day before.

To unmold, run the tip of a thin, sharp knife around the edges of the molds or custard cups. Dip each mold in a bowl of hot water for 5 or 6 seconds if the molds are made of metal. Porcelain or glass custard cups need to be dipped for from 12 to 15 seconds. Invert the molds over individual serving plates and rap sharply to release the eggs.

Drop the hard-cooked yolks one at a time through the processor tube with the motor running. Then feed in the minced parsley and process for a second. Spoon the egg yolk-parsley mixture around each egg to make a "bed" and pass the herb sauce. HERB SAUCE (Makes about 2 cups) 1 egg yolk 1/2 teaspoon dijon mustard 2 tablespoons red wine vinegar Salt and pepper to taste 1/2 cup peanut oil 1/2 cup olive oil 4 tablespoons minced parsley 2 tablespoons minced shallots

Place the egg yolk, mustard, vinegar, salt and pepper in the bowl of a food processor and process for 30 seconds. With the motor running, slowly feed in the peanut oil and the olive oil. Stop the motor, add the minced parsley and shallots and process for another second or two. Turn into a sauceboat and refrigerate, covered, until needed. The sauce can be made a day in advance. BRAISED STUFFED BEEF BIRDS (8 servings) 1 3/4 pounds top round steaks, thinly sliced ( 1/4 inch) For the stuffing: 3 tablespoons butter 1 large onion, minced 1 large clove garlic, minced 1/2 teaspoon thyme Salt and pepper to taste 1 1/2 pounds lean pork loin, trimmed of sinews and ground in the food processor if desired 3 tablespoons medium-sweet or dry madeira For cooking the beef birds: 2 tablespoons vegetable oil 2 tablespoons butter 1 large onion, thinly sliced 1 large carrot, thinly sliced 1 tablespoon flour 1 cup dry white wine 1 cup beef bouillon 4 tablespoons minced parsley

Cut the steaks into 12 rectangles measuring 4-by-5-inches each. Place the pieces between waxed paper and flatten with a meat pounder or the side of a large can.

To make the stuffing, melt the butter in a small frying pan, add the minced onions and garlic and saute' over low heat until transparent but not browned. Add the thyme, salt and pepper and cook, stirring, for another minute. Combine with the ground pork, add the madeira and mix well. Spread each piece of beef with the stuffing and roll so that the finished rolls measure 4 inches long. Use soft butcher's twine and tie the rolls in three places--1 inch from each end and at the middle.

To cook the beef birds, heat the oil and butter in a frying pan and brown the rolls, one or two at a time. Transfer to a heavy casserole as they are browned. Add the carrots and onions to the frying pan and cook slowly until soft and browned. Blend in the flour and cook, stirring, until browned. Add the wine and bouillon to the frying pan and bring to the boil, stirring and scraping up all the browned bits from the bottom of the pan. Transfer the contents to the casserole, cover and bake at 325 degrees for 1 1/4 hours, or until the rolls are tender. Remove the rolls from the casserole, cut off the strings with scissors and discard the strings. Cut each roll in half, using the indentation made by the middle tie as a guide. Stand three halves, cut side down, in each potato nest and ladle the sauce of the meat. Garnish each nest with minced parsley. FRIED POTATO NESTS (8 servings) 4 pounds russet potatoes 2 quarts vegetable oil for deep frying Salt to taste

Peel the potatoes, grate them in the coarse-grate blade of a food processor and turn the shreds into a large bowl of cold water. Soak for about 10 minutes, turn into a colander and rinse under cold water. Drain well, squeeze out as much water as possible, spread on a cloth dishtowel and pat dry. Roll the grated potato in the towel and set aside.

Heat the oil over medium heat in a deep-fat fryer to 375 degrees. Remove the clamps from the potato nest frying and pack the entire bottom basket with a 1/2-inch layer of potatoes. Be sure the potatoes come all the way to the top edge of the basket. Then fit the smaller top basket into the potato-filled bottom basket and replace the clamps. Lower the basket slowly into the hot fat. The oil will bubble up as the basket meets it, so be sure to hold the basket full length and stand back. Fry the potatoes until golden brown. Then remove the basket from the oil, remove the clamps and loosen the potato nest, with the help of a knife, from the top and bottom baskets. Using tongs, return the nest to the fat and fry on both sides until deep brown. Set the nest, right side up, on a jellyroll pan lined with paper towels and drain. Skim off any loose potato shreds in the pot, using a slotted spoon. Check the temperature and fry the next basket when the oil is 375 degrees. Continue until all the nests are made and sprinkle each with a little salt. The nests can be made several hours in advance and recrisped, if necessary, in a 350-degree oven for a few minutes before filling. ASPARAGUS SHEAVES (8 servings) 40 medium-thin spears asparagus (about 3 1/2 pounds) 8 to 10 long, green strands from scallions 1 tablespoon melted butter

From each asparagus spear, cut a 5-inch piece from the tip. Reserve the bottom end of the stalk for soup or other uses.

Bring water to the boil in a large frying pan and blanch the scallion strands for about 10 seconds. Remove to a paper towel. Then cook the asparagus tips in the water for about 5 minutes, or until they are just done. Remove to a cloth towel, pat dry and tie them, using the scallion strands, into 8 sheaves of 5 tips each. Set a sheaf upright on each dinner plate and dribble with butter. APRIL FOOL (8 servings) 2 10-ounce packages frozen raspberries, defrosted 2 egg whites 1 cup heavy cream Fresh raspberries for garnish (optional)

Turn the raspberries into a strainer over a bowl and let them drain. Reserve about 5 tablespoons of the juice for the fool. Place the raspberries into the food processor with 2 tablespoons of juice and reduce to a pure'e. Push the pure'e through a strainer and discard the seeds. The pure'e can be made a day in advance.

To assemble the fool, beat the egg whites until they are stiff but not dry and fold into the pure'e. Whip the cream and fold into the raspberry mixture. Divide among 8 champagne or wine glasses and spoon about 1 teaspoon of the remaining juice into each glass. Garnish, if possible, with whole fresh raspberries or raspberries frozen without sugar the summer before. The fool will hold in the refrigerator for a few hours. Bring to room temperature before serving.