Is it soup yet? Is it cake yet? Is it roast yet? Is it custard yet? How can you tell when it's done?

Beginning cooks may wonder at the complexities of knowing when food is just right. Once you've done the chopping, the measuring, the mixing, you certainly don't want to overcook, much less burn the food. Nor do you want to serve it still raw or runny in the middle.Some experienced cooks can actually tell by smell that something, of-ten cookies or bread, is done. Other cooks go into a hovering pattern, checking a food every minute or so when they think it's just about done. My experience has been that foods get done sooner than you expect, so I set the timer five or 10 minutes short of the predicted finish time.

Happily, the advent of the microwave oven makes it possible to quickly reheat a food that has gotten done way ahead of other foods being served at a meal. And, when a casserole or an egg entree lags behind the rest of the meal, it can be hurried by switching from the conventional oven to the microwave.

Different types of foods require different tests for doneness. If you're using a published recipe, look for the phrase starting, "or until" that should appear right after the cooking or baking time.

But if you're using a hand-me-down recipe or one from a church or community cookbook, written by and for longtime cooks, the tests for doneness below should be helpful.

Food thermometers are a great help in dealing with meat, poultry and candy - they're a wise investment.

These tests for doneness are meant to be guidelines, not hard and fast rules. Cut them out and pin them up some place where you can consult them quickly as you cook.

Breads, quick (muffins, biscuits): Bake until golden brown.

Breads, yeast: Tap crust lightly; if done, it will sound hollow.

Cakes, butter-type, or sweet quick bread loaves: Stick a toothpick into the center of the cake/bread. If it comes out clean, it's done.

Cakes, egg-lightened, such as angel food and sponge: Touch top lightly, gently; if it springs back, it's done.

Casseroles: When bubbly. If there's a topping or crust, it should be golden.

Cookies: Uniform size is important for even baking. Drop cookies should be set and golden brown around edges. If using a new recipe, it's smart to bake one cookie (alone on the sheet) as a test: If it spreads too much, you need to add a tablespoon or two of flour. Bar cookies should begin to pull away from sides of pan.

Egg custards and quiches: Insert knife in center; if it comes out clean, food is done.

Fish: Fillets, steaks and whole fish will flake when done and flesh will be opaque. Remove from pan immediately so residual heat doesn't continue cooking and thus toughen fish.

Meat (beef, pork, lamb, veal): Decide whether you want rare, medium or well done, then consult timing chart in basic cookbook such as "Betty Crocker's Cookbook" (Golden Press, New York). To test roast or steak, cut into flesh with sharp knife and check amount of red/rareness. If you'd rather not cut the meat, which allows juices to escape, poke a lean surface with your clean finger. The meat is rare if the flesh yields readily; more resistant meat is medium rare; firm meat is well-done.

Pasta: Using wooden pasta fork, pull up a strand or two of pasta. Let it cool briefly, then taste (don't burn your tongue) to see whether it can be bitten through easily; then it's al dente, literally "to the tooth."

Pies, fruit: Juice will start to bubble through slits in top crust; test to see whether fruit is tender by inserting fork in a slit.

Poultry: Pierce meaty portion of chicken or turkey with two-tine kitchen fork. If juices run clear, it is done. If they run pink, cook a little longer, until juices are clear.

Seafood: Shrimp and other shellfish such as lobster change color when done, usually turning from grayish green to pinkish white.

Vegetables: Push kitchen fork into vegetable to check tenderness; vegetables are best when tender-crisp, not soft. The exception is baked potatoes, which should be soft to touch when done and push up, fluffy, when cut.