THE ANNUAL COLLISION between untold thousands of potentially wonderful tomatoes and the hard frost that will turn them all to mush is one of the immutable facts of nature. Immutability aside, however, it is a fact that tends to craze even the most reasonable people. "I can beat this thing," they say to themselves, staring down at the vines.

One man, normally the soul of equanimity, once wrapped 1,000 green tomatoes individually in newspaper, believing they would turn into 1,000 red tomatoes as the winter wore on. Believing did not make it so, and of course he ended up with a lot of individually wrapped, rotten green tomatoes.

Then there was the man who removed half a dozen entire tomato plants from the ground, roots and all, and took them to his basement, where they hung upside down from the rafters and dropped dirt, leaves, twigs, and finally toward Christmas, rotten tomatoes. Reminded now that he did this, he chooses to believe that it worked. As co-owner of the basement, I can say that it did not work.

What none of us knew is that an immature green tomato will never be anything but an immature green tomato. Allison Brown, of Garden Resources of Washington, a non-profit organization dedicated to helping urban gardeners get started and then stay out of ridiculous predicaments like the ones above, points out that color has nothing to do with maturity. Mature tomatoes are those that have reached full size and whose seeds are movable and not held firmly in place. They can be just as green as the next tomato, but these mature tomatoes are the ones that will ripen.

Deciding which tomatoes are mature involves a certain amount of guesswork, since you can't cut into every one. Obviously those that have begun to show red are good candidates for ripening indoors, as are the ones that appear to be maximum size for the variety.

Once you've chosen the keepers, bring them inside and either wrap them or lay them on racks and store in a cool dark place. They should not touch one another, as rot and mold spread quickly, and they should be checked often to ferret out any that might be spoiling. Proponents of the bring-in-the-whole-plant school of thought claim that this method really does work with mature tomatoes. Besides being messy, however, white flies can be transported indoors this way.

It is possible, with some effort, to have ripe red tomatoes through December. But for immature green tomatoes that are destined to stay immature green tomatoes, here are a few recipes. GREEN TOMATO FRITTERS (4 servings) 3/4 cup corn meal 1 teaspoon sugar 1/2 teaspoon salt 1/2 teaspoon baking powder 3/4 cup milk 1 egg, beaten lightly 3 or 4 medium green tomatoes Oil for deep frying

Mix dry ingredients. Beat egg lightly with milk, then add to dry ingredients and stir until lumps are dissolved. Core and peel tomatoes, using a paring knife or vegetable peeler for peeling. Slice about 3/8-inch thick and dry on paper towels. Heat oil to about 375 degrees. One by one, dip tomato slices in batter, then drop carefully into hot oil. As tomatoes bounce to surface, turn over. When brown, remove from oil and drain on paper towels. Serve hot. SWEET GREEN TOMATO TART (8 servings) For crust: 1 1/2 cups flour 3 tablespoons sugar Pinch salt 1 stick unsalted butter, cold 5 tablespoons ice water For filling: 4 cups peeled, cored and chopped green tomatoes (about 1 3/4 pounds) 4 tablespoons butter 3/4 cup sugar 1 teaspoon grated lemon rind Pinch freshly grated nutmeg 1 egg 1/2 cup whipping cream Powdered sugar for dusting

Using a paring knife or vegetable peeler, peel and core tomatoes. Slice 1/4-inch thick, then cut the slices into 1/4-inch cubes. There should be 4 cups. Let drain in a colander while you prepare pie crust.

To make crust, combine flour, sugar and salt in the bowl of a food processor fitted with the steel blade, or in a regular mixing bowl. Cut cold butter into 1/2-inch pieces, add to flour mixture and process or work with knives or pastry blender until mixture looks like coarse corn meal. If working by hand, add ice water 1 tablespoon at a time, working into flour gradually. If working with a food processor, add ice water slowly through feed tube while processing, and process only until mixture starts clumping up on the sides. Don't let it form a ball. Roll dough out immediately into a 12-inch circle and use it to line an 11-inch tart pan. Refrigerate.

Melt butter in large saute' pan. Add tomatoes, and cook stirring, over high heat, for about 5 minutes or until moisture is evaporated. Add sugar and cook, stirring, for another 5 minutes, until liquid is very thick.

Season tomatoes with lemon rind and nutmeg, then set aside to cool.

Whisk together egg and cream until well blended. Spread cool tomato mixture in lined tart pan and pour egg-cream mixture over all. Bake at 450 degrees for 5 minutes, then turn oven to 375 degrees and bake 30 to 35 minutes longer, until top is brown and tomatoes are tender. Serve warm or at room temperature, dusted lightly with powdered sugar. GREEN TOMATO PROVENCAL (4 to 6 servings) 1/3 cup chopped parsley 4 garlic cloves 4 medium green tomatoes, preferably spherical rather than very wide 2 tablespoons good olive oil Salt and pepper Sugar 1/2 cup bread crumbs

Chop garlic and parsley together. Core tomatoes and cut in half crosswise. Dig out as many seeds as you can. Heat oil in large saute' pan and let tomatoes cook slowly, cut side down, for about 10 minutes. Turn over and cook slowly on the other side for about 10 more minutes, or until tomatoes are almost tender.

Remove tomatoes to an oiled baking pan or gratin dish. Sprinkle lightly with salt, pepper and sugar, then with garlic-parsley combination and finally with crumbs. Drizzle over them the oil from the saute' pan.

Bake in a 400-degree oven for about 10 minutes, or until nicely brown on top. Serve warm.