IN A LARGE MIXING BOWL STIR TOGETHER THE FLOUW, SUGAR, BAKING POWDER AND SALT. MAKE A WELL IN THE CENTER. COMBINE EGG, MILK AND OIL. ADD EGG MIXTURE ALL AT ONCE TO FLOUR MIXTURE. STIR JUST TILL MOISTENED; BATTER SHOULD BE LUMPY. GREASE MUFFIN CUPS OR LINE WITH PAPER BAKE CUPS; FILL 2/3 FULL. BAKE IN A 400 DEGREE OVEN FOR 20 TO 25 MINUTES OR TILL GOLDEN. REMOVE FROM PANS; SERVE WARM. MAKES 10 TO 12 MUFFINS. VARIATIONS ADD: BLUEBERRY: COMBINE 3/4 CUP FRESH OR FROZEN BLUEBERRIES, THAWED, AND 2 TABLESPOONS ADDITIONAL SUGAR. APPLE-RAISIN: STIR IN 1/2 TEASPOON GROUN CINNAMON INTO FLOUR MIXTURE. FOLD 1 CUP COPPED PEELED APPLE AND 1/4 CUP RAISINS INTO BATTER. JELLY: SPOON 1 TEASPOON JELLY ATOP BATTER IN EACH MUFFIN CUP BEFORE BAKING. DATE-NUT: FOLD 2/3 CUP COURSELY CHOPPED PITTED DATES AND 1/3 CUP WALNUTS OR PECANS TO BATTER. CHEESE: STIR 1/2 CUP SHEDDED CHEDDAR OR SWISS CHEESE INTO FLOUR MIXTURE. BANANA-NUT: DECREASE MILK TO 1/2 CUP. STIR 1 CUP MASHED BANANA AND 1/2 CUP CHOPPED NUTS INTO BATTER. PUMPKIN: INCREASE SUGAR TO 1/3 CUP. ADD 1/2 CUP CANNED PUMPKIN TO EGG MIXTURE. STIR 1/2 TEASPOON GROUND CINNAMON AND 1/2 TEASPOON GROUND NUTMEG INTO FLOUR MIXTURE. STIR 1/2 CUP RAISINS INTO BATTER. CRANBERRY: COURSELY CHOP 1 CUP FRESH OR FROZEN CRANBERRIES AND COMBINE WITH 1/4 CUP ADDITIONAL SUGAR. FOLD INTO BATTER.