Think dad and you invariably think meat and potatoes. A fallacious association, perhaps, but pervasive nonetheless. Men, in any case, never seem to feel guilty if they have put relatively little effort into a perfectly reasonable meal. They enjoy it as if it were squab stuffed with pa te' de foie gras.

Thus, they readily appreciate the integrity of the three-item menu--meat, potatoes and vegetable--without worrying about sauces or proper courses. Father's Day paves the way for tasteful simplicity and establishes a precedent for easy, satisfying menus.

Roast beef might be the prime candidate for such a meal, but it's expensive and not the most suitable summer entree. Flank steak, leaner and cheaper than meat from the rib, can be replaced by club, sirloin or strip steaks as the budget allows.

Those who have avoided flank steak need not be intimidated by this peculiar piece of meat. Unlike other tough cuts, this one takes well to the quick cooking that is traditional to more tender rib and loin steaks. Tenderness comes from proper carving.

Proper carving has other advantages. Laying the knife flat on the top of the meat and slicing on a very gradual slant (begin a little off-center) will yield broad slices resembling those from a large roast. This way, people who prefer well-done meat can eat the outside pieces; those who enjoy rare can wait for the middle slices. Slices should be about 1/8-inch thick.

To cook steaks properly, coals should have burned down to an even gray. The meat should be brushed with vegetable oil and laid on the grill very close to the coals. After the meat has seared on both sides, the grill should be raised about 5 inches from the coals to complete cooking--a process that takes about 5 minutes.

Potatoes Anna--a decadent, buttery variation of oven-fried potatoes--play their role perfectly. For any dish that has such honest flavors as this, just butter and potato, freshly ground pepper is imperative. Creamed spinach, which appears on many of the country's most macho menus, rounds out the masculine meal.

Every kitchen should be stocked with flour, sugar, salt, pepper and oil and/or butter.

EXPRESS LANE LIST: flank steak, wine, garlic, russet potatoes, spinach (fresh or frozen), milk or cream, nutmeg, parmesan cheese. DAD'S FLANK STEAK (4 to 6 servings) 1 flank steak (about 2 pounds) 1/4 cup vegetable oil, plus more for brushing 1 cup red wine 2 garlic cloves, mashed 1/2 teaspoon salt 1/2 teaspoon freshly ground pepper

Place the meat in a plastic bag with oil, wine, garlic, salt and pepper. Tie securely, place on a plate and allow to marinate at room temperature for 1 to 2 hours, or refrigerated for the day. (The marinating is optional; proper carving will render the meat tender.)

Heat the charcoal until it has burned down to gray ash. Remove the meat from the marinade, brush it with oil and place it on the grill very close to the coals. Cook for 1 minute, then flip the meat. Cook another minute, then raise the grill about 5 inches away from the coals. Cook 4 to 5 minutes for rare steak, 5 to 6 minutes for medium rare.

Remove from fire, slice as described above. POTATOES ANNA (4 servings) 4 large russet potatoes Butter Salt and freshly ground pepper

Butter a shallow baking dish or skillet (with oven-proof handle). Wash and slice potatoes in thin slices. Place a layer of potatoes on the bottom of the baking dish. Sprinkle with salt and pepper and dot with butter. Add another layer of potatoes and repeat with salt, pepper and butter. Repeat the process until all potatoes are used. Dot the top with butter and bake the potatoes in a 400-degree oven for 40 minutes or until the potatoes are crusty on top and tender in the middle. Invert the baking dish on a serving plate and serve. CREAMED SPINACH (4 servings) 10 ounces fresh or frozen chopped spinach 1 1/2 tablespoons butter 3 tablespoons diced onion (optional) 1 tablespoon flour 1/2 cup milk, evaporated milk or cream 1/4 teaspoon ground nutmeg 1/2 cup parmesan cheese

If using fresh spinach, clean, trim and chop it. Steam in very little water until the spinach wilts. Drain well. If using frozen spinach, allow it to thaw and drain well. Melt butter in skillet. Add onion, if desired, and cook until transparent. Add flour and cook for 1 minute. Whisking constantly, stir in milk, then season with nutmeg. Add spinach and put the mixture in a small casserole. Top with grated cheese (substitute cheddar if desired). Bake at 350 degrees for 15 minutes, or until cheese is melted (or finish in the oven while the potatoes are cooking--bake about 10 minutes).