Okay, it's your turn to cook dinner but . . . nothing seems right. They happen to the best of cooks, those evenings when you draw a blank. And time is running out. What to do? Well, why not just start cooking now and ask questions later?

Fine, but cook what? You might consider the basic, all-purpose starter meal. Slice some onions into a frying pan. Add a chopped pepper. Some minced garlic. Some salt and pepper, some chopped tomatoes, some ground meat. At this point, your background takes over. If you happen to be Italian, you'll reach for the oregano and the spaghetti. Indian - and you'll want some curry and rice. Hungarians will go for noodles and paprika.

But on this particular night, the accent is Mexican. Tonight you'll rely on the South-of-the-Border spices and make tacos that will be the envy of fast-food stands everywhere.

The Staples: Make sure these are all on hand: garlic, oregano, chili powder, cumin, coriander, Tabasco, salt, pepper, butter.

The Shopping List: One pound ground beef; one large onion; three large tomatoes, one package tortillas (frozen or dried); two green chili peppers (carefully seeded); half pound cheddar cheese; a head iceberg lettuce one small can tomato sauce; two ripe avocadoes; one melon; one lemon; one lime; beer.

Any taco recipe quickly becomes the original creation of the person doing the cooking.It's one of those meals that you bend to your own taste almost immediately. So what follows should not be considered a recipe so much as a starting point.

5:30 PM: And the way you start the taco sauce is much the way you start a spaghetti sauce. Begin by frying the ground beef in a large frying pan over medium heat. When the meat is browned, drain away the fat and set the beef to one side.

Melt a chunk of butter in the frying pan and add half the onion, chopped fine. And two cloves of garlic, minced. And the seeded green chili peppers, minced. Simmer this over a medium heat for 10 minutes and then add the tomato sauce. Add a pinch of oregano, a pinch of cumin and another of coriander.

And now the chili powder. How much chili powder? Well, before making a decision of this magnitude, you must ask yourself this question: How much cold beer do you have on hand?

Try two tablespoons of chili powder, more if you like things hot. Finally, add the cooked meat. Keep the mixture warm over very low heat until you serve it.

5:50 PM: Grate the cheddar cheese and chop half a head of lettuce and set this aside.

Cook the tortillas, following the directions on the package. Tortillas can be purchased in a dried or frozen form. Whichever you choose, you'll wind up with a corn pancake that forms a pocket for the taco filling.

6 PM: Guacamole is traditionally served as an appetizer, a dip that is generally accompanied by crackers. Tonight, however, it will be your salad. Make the guacamole as close to dinner time as possible as it has an unfortunate tendency to turn brownish.

Rub the inside of a small bowl with a peeled clove of garlic and then throw it away. (The garlic, not the bowl.) Peel the ripe avocados and mash them with a fork. Add the juice of half a lemon, the rest of the chopped onion, a few dashes of Tabasco sauce, freshly ground pepper, salt and one medium-sized tomato, chopped fine.

6:30 PM: When a meal is this simple to put together, appearance counts. Serve the chilled beer in a proper glass. Scoop the guacamole onto a nice bed of lettuce. Serve the melon slices with a wedge of lime.

The tacos themselves will have to be individual creations. The meat mixture is spooned inside the folded tortilla and is then topped by a handful of chopped lettuce and grated cheese.

Now bite into it. Ah! It should be spicy - hot to the mouth and warm to the stomach. And it should be followed, in short order, by a long beer. For this is a scientific fact: The only known antidote to the well-made taco is the properly chilled beer.