A is for apple, as in apple sauce tucked around a helping of roast pork, apple pie, hot for dinner and cold for breakfast with a slice of cheddar cheese, apples baked and apples bobbed for, but A, just as it settles down to being about apples, is also about Autumn.

Summer may need a good kick to get it out of the way, but the seasons do change and with the cooler weather comes the return of forgotten favorites.Bonfires, for example, and if many municipalities have changed the smell of fall by banning the burning of leaves, there are other ways to recall the hazy days of autumn.

Invite apartment-dwelling friends over for an afternoon of raking and an evening meal cooked outside. (If you invite friends with leaf-laden lawns of their own, expect to be met with howls of laughter.) If some of the leaves were to find their way into the cooking fire and perfume the air and the meat, you probably would not be thrown in jail. C is for cider, thick and unpasteurized and sold at a hundred roadside stands, to be served alone or jiggered up a bit with rum and spices.D is for door, and it's high time you found out whether people can find your's. Drive past your house after dark, which is when most of your guests arrive. Can you see the numbers? If not, buy new ones and put them where they can be seen.E is for Equinox, Autumnal, which occurs Sept. 23 at 9:42 a.m. Toast the new season.F is for fatwood, the Georgia pine that is so resin-soaked that one or two sticks will start the most reluctant fire. Buy a sack of the kindling ($14 from L.L. Bean, Inc., Freeport, Maine 04033) and end those awful moments when the fire refuses to catch and all guests are called on to blow the flames back to life.G is for goose. There is an old custom which says it must be eaten on St. Michaelmas Day, Sept. 29, if you want to be plump in the pocket for the rest of the year. Share the bird with friends who owe you money.H is for hot chocolate. Make it in the Mexican fashion (for four cups, combine four squares of unsweetened chocolate, 4 cups milk, 1 teaspoon ground cinnamon, 1/2 teaspoon ground cloves, 1 teaspoon vanilla and sugar to taste, heat until the chocolate is melted and then whip with an electric beater until it's frothy) and serve it to friends on the first cold night. (H also is for harvest moon, which will be full Sept. 22, a good night to howl.)I is for Indian pudding, a richness of cornmeal and molasses that is much too heavy to eat during the summer and much too delicious to ignore in the fall. Serve a New England boiled dinner and round it off with the Indian pudding, quivering in a sea of heavy cream or topped with a scoop of vanilla ice cream.J is for juniper berries. Throw six or seven in the pot the next time you make beef stew.K is for kasha--buckwheat groats, which are an interesting change from potatoes or rice. Cook it the way you would rice, though to keep the groats from mushing together, break an egg into a frying pan, stir in the groats and cook over low heat until they've absorbed the egg. Then add 2 cups beef broth for each cup of groats, cover and cook 10 minutes over low heat until tender. Serve with butter.L is for lentils and all the other legumes, which provide us with the thick soups of winter.M is for mulled wine. To a quart of red wine, add the peel of an orange and a lemon, a cinnamon stick, six cloves, and a tablespoon of sugar and simmer for 10 minutes.N is for nuts, big bowls of unshelled walnuts put out instead of more complicated appetizers. If you don't have a nutcracker, go out and buy one,O is for oatmeal and the return of the Sunday brunch in a heartier form. Serve oatmeal and johnnycakes and country ham.P is for pumpkin, which need not be limited to pies and jack o' lanterns. Make pumpkin soup and serve it in a hollowed out shell. Or make pumpkin pudding or pumpkin bread.Q is for quail and the return of game. The plump little birds are sold at Arrow Live Poultry Co., 919 5th St. NW, 789-9422, and at Market Poultry, 225 7th St. SE, 543-7470, in the Eastern Market, among other places.R is for red wines and the return of lush burgundies, but it also is for root vegetables and the unimaginative way we use them. This fall, find at least one unusual way to serve carrots, potatoes, rutabagas, turnips or beets.S is for sherry and a rainy afternoon spent with three or four close friends sipping dry sack, nibbling on biscuits and listening to sentimental songs (which is another thing S is for). Play Frank Sinatra crooning "Autumn in New York," or "September Song," and tell each other very sad stories as the fire burns down and the year slips away.T is for taffy. Did you ever have a taffy pull? Basic cookbooks carry the recipe and even if you all wind up a candied mass, you'll have fun trying.U is for update, which is what you should do to your address book. Go through it now and call all the friends you know have moved for their new addresses. It's much easier to do it now than before a large party, when you'll be busy with other things.V is for venison, which should be available in the market in the next few weeks. Check the following stores, all of which will be carrying it, to see if it's in stock: Georgetown Boucherie, 3206 Grace St. NW, 333-3206; French Market, 1632 Wisconsin Ave. NW, 338-4828, and Union Meat Company, the Eastern Market, 547-2626.Wis for wood. Order a cord now so that the first cold night won't find you cursing an empty hearth.Xis for xylophone. Rent one from Music & Arts Center, Inc., and give a musicale. The company has stores in Maryland and Virginia. A bell kit rents for $20 for three months, plenty of time to practice. Wear a mask if you're embarrassed. Buy masks for all your guests if they are. A masked xylophone musicale. You'll be the only person on your block giving one.Y is for Yorkshire pudding, to serve with your roast beef. Don't worry. It's supposed to look like that.Z is for zucchini and the impossibility of stopping the damn things. Celebrate the end of summer and the beginning of autumn by going into the garden and pulling up every single plant.