IT'S THE ALL-AMERICAN LUNCH; the roadside fast food; the Fourth of July back yard barbecue. And it hasn't changed much - despite names like Big Mac, Mighty Mo, Bacon-Cheeseburger - since it was introduced at the St. Louis World's Fair in 1904 and a whole country discovered eating without forks was fun.

In Washington, the variety of hamburgers ranges from a good little counter patty for eighty-nine cents at Peoples to a big-bucks extravaganza on special order at the Rive Gauche. In between are as many hamburger platters as there are Washington pubs and an amazing distance between the best and the worst. Cooking isn't all that makes the difference - not to mention that price is no indication either. A good hot hamburger between the bun starts with good hamburger, which is to say ground beef that is not more fat than meat (See box). But even then you are not home free with a hand-held feast.

Below is but a selective smattering of hamburger offerings in Washington.

****The Charing Cross. Even though it's Italian-oriented, the Cross has a hamburger at noon that is juicy and full of taste, served with, not on, slices of toasted Italian bread, and accompanied by a romaine salad with well-put-together dressing and french fries. A great meal.

****Cafe de Paris. It's billed as a French hamburger but it comes closer to the all-American hamburger than any I have eaten since Hamburger Heaven in New York closed. A moderate amounted of minced onion that must have been cooked before being incorporated with the ground meat was a welcome addition, and the dish came rare as ordered. It was served on slices of French bread with unpeeling French fried potatoes, really first rate, with endive and raw cauliflower salad beautifully dressed.

****Old Europe. Their Deutsches Beef Steak, which is surprisingly low in fat content (thirteen per cent) considering it is eighty per cent beef mixed with pork, is to be applauded. You can have it rare if you wish, for the pork has been frozen, thus eliminating the remote possibility of trichinosis according to competent sources. It is served with an onion sauce and topped with a lightly fried egg.

***Rudy's (McLean). An excellent lean hamburger. The ten per cent, low-fat content pays off.

***Intrigue.Another lean - twelve per cent fat - hamburger that comes off with merit in the cooking. Done right and exactly as you ordered it.

***Clyde's, and the Old Ebbitt Grill. Commonly owned, both establishments do best, despite all the fancy new menu additions, with their classic P.J. Clark-type hamburgers. The bacon cheeseburger are always worth the trip and the meat of the hamburger is a nice fifteen per cent beef fat, normally cooked just as you ordered. Imitators are still trying to top Clyde's and the Ebbitt's bacon cheeseburgers and the disc-shaped deep-fried potatoes that come with - but they'll have to keep trying still.

***The Monocle. My last visit uncovered a marked improvement over the hamburgers of yore. A nice fourteen per cent fat content variety was much better than lunches last year when I'm sure the hamburger fat content was much higher.

**The Prime Rib. A beef house with hamburgers that are made from fourteen per cent sirloin and served in about twelve-ounce portions should be a winner. Alas, the ones I've sampled have all arrived overdone. Only the middle was rare as ordered. All of it should have been that way.

**Hamburger Hamlet. Another specialty house that should do better. A lot of variety with umpteen kinds of hamburgers, but, when you get down to the plain truth, it's just passable.

**Howard Johnson's. The frankforts on buttered buns are terrific. Too bad the hamburgers aren't.

**The Warehouse (Alexandria). Nice presentation and the product is reasonably good . . . but nothing memorable.

**The Tombs. Sixteen per cent beef fat. Edible, but not great.

**Third Edition. Another sixteen per cent beef fat burger that's nothing to write home about.

*Nathan's. At eighteen per cent, the hamburger was not only high on fat but was stringy from grisly content, and the patty was packed so tightly that it never would come out right regardless of the content.

McDonald's Burger King, Burger Chief and Little Tavern. They're all on a par which is way below par: vastly overcooked; masked with condiments that would kill the taste of even a good burger. Drek.

The shorter the time between grinding and cooking hamburger the better the dish will be. Grind your won, although good results stem from meats freshly ground in chain stores.

The cut of beef for hamburger depends on taste and budget. It seems a shame to grind a first-rate sirloin, although bits of this part of the animal can be reasonably economical and fine tasting. Chuck is fairly low-priced, and has a reasonable amount of fat; the center chuck is the choice of the best restaurants and Julia Child. Round has less taste.

My choice is flank steak, which at this writing is about $2 a pound and makes one of the most delectable hamburgers: lean, yet juicy and with great taste.

Handle hamburger as gently as if it had some of the properties of nitroglycerine. Press it only enough to form it into the thickness and shape you want. Once on the fire, don't press it with a spatula, which merely gums up the mass. Some chefs recommend a bit of ice or cream in the middle of a thick patty to keep the result rare. I have never found this necessary.

Virtually the same cooking rules apply to hamburger as to steak. Charcoal fires are ideal; lump (natural-kilned wood) rather than briquettes (ground wood with a binder) is best both for producing intense heat and no fumes other than those of natural wood.

Most home broilers do not provide the heat of commercial ones, which get up to 800 degrees. That heat insures a crusty exterior and a rare center. But don't rule out a home broiler; be sure to preheat it for about fifteen minutes and use the rack next to the top from the flame.

Pan cooking is fine. Some chefs recommend heating a heavy skillet thoroughly, coating the surface with salt and cooking the hamburger on both sides until a crust forms. Others prefer butter or fat. I think a Teflon-coated pan is ideal; for without splatter or fuss the patties can been nicely browned and then cooked to the degree of doneeness you like.

How to treat a hamburger with seasonings and other elements is obviously a matter of taste. There's nothing wrong with just a grinding of pepper, a bit of salt, especially if the hamburger is of high quality and is cooked fairly rare. A pat of butter with dill or parsley just before serving helps greatly.

However, the number of variations to this go-easy formula are legion, and some of them are estimable. Hamburger has an affinity for nutmeg and allspice, added in small quantity before cooking. Onion and celery, finely minced, provide moisture and flavor.

But if anything is to be added, I prefer to do so as a stuffing, which is described admirably in Nika Hezelton's Hamburger! (Simon and Schuster, New York.) The author says to use about a pound and a half or two pounds of ground meat flattened into a rectangle about six by twelve inches. With a spatula dipped in oil, cut eight equally sized squares. SPread or place the stuffing you wish on four of the squares. Cover with the other squares. Crimp the edges with your fingers dipped in water or cooking oil. This keeps the stuffing in while the burger is cooking. (Mrs. Hazelton recommends that the corners be rounded, but I don't see the necessity for that.)

The merit of this method of adding to hamburger is that it involves handling the ground meat very little, which is one of the musts in making good hamburgers. Moreover, you can invent your own stuffing, depending on your taste. Here are some stuffings I like particularly:

Anchovies. Use the filets, and select the slightly higher-priced ones (such as Roland) if you are shopping in a chain store. The difference is noticeable and the price not budget-breaking. Season the hamburger with pepper but no salt because the anchovies are highly salted. Lay about four of five filets on the under square of hamburger and fit on the top. With this and other stuffed versions, cook to the desired degree of doneness.

Boudin noir. This is the French pork and blood sausage obtainable at the French Market in Georgetown. Remember, the boudin is already cooked, so all you have to do is prick the skin with a fork so the steam can escape while it is heated in the oven or water. Cut the sausage lengthwise and scoop out the inside and spread on the hamburger square.

Pate. Treat this the same way as the boudin, except that the heating of the pate is best done in a pan. You might say that this is the poor man's tournedos Rossini, and indeed, if your budget is tight, a good grade of liverwurst can take the place of the pate with commendale results.

Caviar and sour cream. Lumpfish, not Beluga obviously, is the grade for this. I had a demurrer from some members of my family when I served this recently, but I made it again and think it is worth eating; in fact, I liked it.

Olives. I prefer the ripe ones, finely minced, but the green, with their various stuffihgs, also lend a bit of panache to a hamburger.

Oysters. This is the hamburger version of the carpetbag, sometimes called the carpetbagger or pocketbook, steak. Poach select-sized oysters in their juice with a dash of Worcestershire until they just barely begin to plump, and use two or three to each hamburger. I've tried this with mussels and thought the dish came off well - more economical than oysters, too.

Spinach. The great affinity that spinach has with beef comes through in this treatment. Well-seasoned pureed spinach is best, but chopped spinach with the water squeezed out will serve well.

Onions. Cook them until just translucent, or longer if such is more to your taste.

Cheese. Take your pick of what pleases you, but stay away from processed cheeses and the "analogs," those synethic products that pretend to be cheese substitutes. For my palate, the best cheese to marry with hamburger is the Yugoslavian kashkaval, made from sheep's milk. You can find a burger made with this at Rudy's, a restuarant in McLean, and cheese shops in the Federal City sell the cheese.

Returning to plain hamburgers, that is, not stuffed, one done in the style of steak au poivre comes off admirably. Use coarsely cracked peppercorns and push them into the hamburger with the palms of your hands. Pan cook to the degree of doneness you wish. Remove the hamburger and add a tablespoon of brandy per portion, flame it, add a pat of butter per serving and pour over the burger.

Also, for a slightly dressedup hamburger, one can borrow from the original recipe for steak Diane. I say original, because it is simple and doesn't overwhelm the meat with strong sauces, which is the case with the steak Diane made in most restaurants today. When the hamburger is cooked in pan, remove it. For a single portion add a tablespoons of dry sherry, a dash of Worcestershire sauce, a bit of Dijon mustard and a tablespoon of chive or parsley butter. Mix all this well until it comes to a bubbling temperature, and pour it over the hamburger.