THERE ARE two kinds of people in the world: Those who love soft-shell crabs and those who've never tried them. Having been introduced to soft-shells late in life, I can well understand the reluctance that even seafood aficionados feel about taking that first bite. But soft-shells are well worth biting into. Their shells are soft because of the blue crab's moulting process. The crab has just shed its hard shell, and the new one is only forming. Think of it as a crab in dishabille and you'll have the right idea.

The end result looks like a crab. The new shell-to-be is already there, but everything is soft. Not only soft, but tender and meaty. With a minimal amount of cleaning (which the fish merchant will do) and speedy cooking, the crab's soft shell becomes slightly crunchy, taking on a crisp, papery texture. Every bit of the cooked crab is edible so the crunchy legs and hunks of crab meat are readily accessible.

Like other aficionados, I've tried to search out the best preparations of the delicacy and the restaurants that do it best. One winner is the soft-shell crab tempura at the Mikado Restaurant, 4707 Wisconsin Ave. NW. s

The secret is simplicity. Coated with tempura batter and then quickly deep-fat fried, the crabs are enveloped in an airy, crisp batter accompanied by a soy-based dipping sauce.

Fortunately head chef Masahiro Uenoyama steafastly refused to use frozen soft-shells in the preparation, but that also means that soft-shell crab tempura is a short-lived seasonal special at the Mikado. As a result, it is wise to make sure that soft-shells are on the day's menu. Soft-shell crab tempura is available a la carte for $6.75 or as part of a five-course dinner for $12.95.

If you'd like to try the tempura method at home during the remainder of the summer-long shedding season, Chef Uenoyama's recipe follows. MIKADO'S SOFT-SHELL CRABS TEMPURA (2 servings) 6 fresh, live soft-shell crabs (not frozen) 1 egg yolk 2 cups water Pinch of baking soda the size of a pea 2 cups all-purpose flour 1/2 cup cornstarch Soy salad oil (for deep-fat frying)

If crabs aren't prepared, turn each crab belly up and remove the apron or pop-top-like flap. Turn over, lift the end flaps of the top shell and remove the spongy sections known as the devil's fingers, or gills. Wash, pat dry and then in the belly-up position cut about a quarter inch off the front of the crab to remove the eyes.

Pat flour along the newly opened surfaces of the crab, including under the top shell, to prevent water leakage during frying.

Once the soft shells are cleaned and ready, the tempura batter can be prepared. (It should not be made until just before it is used.) Combine the egg yolk, baking soda and water in a bowl, mixing thoroughly. In another bowl, mix the flour and cornstarch until well blended. In several batches add the flour to the liquid mixture. It is very important not to overmix the ingredients; for the best results use chopsticks in a hitting or chopping motion. Do not use the conventional stirring motion. The end result should have a number of lumps. Add 2 to 3 ice cubes to the finished mixture to keep it from thickening further.

When the oil reaches a temperature of 340 to 355 degrees, it is ready for frying. (The temperature is right when a drop of tempura batter submerges slightly, then rises to the top and browns in about 45 seconds.) Each crab should be dipped individually in the batter just before cooking. To do so, hold the end flaps of the top shell out of the batter and dip the crab in belly side down. Make sure the legs and area under the top flaps are coated but that the top shell is not. Remove the crab from the batter and make a batter thumbprint on the center of the top shell. Slide the crab into the hot oil, belly side down, and cook for about 1 minute. Turn it over and cook on the other side for about 1 minute. When crisp and brown, remove the crab to a piece of absorbent paper for a moment. Between cooking each crab skim away any loose drops of batter in the oil. Serve the crabs while hot and crisp with the dipping sauce. SOFT-SHELL CRAB DIPPING SAUCE 1/4 cup soy sauce 1/4 cup mirin (Japanese sweet cooking rice wine) 3/4 cup water 1/4 cup shaved bonito flakes 2 tablespoons grated daikon (white radish) 1 teaspoon grated fresh ginger root

Combine the soy sauce, mirin, water and bonito flakes in a saucepan and bring to a boil. Then continue to simmer the mixture until serving time. In each of two dipping bowls place 1 tablespoon of the grated daikon and 1/2 teaspoon of grated ginger root. Strain (to remove the bonito flake) before pouring into the two dipping bowls.