Combine 1 1/2 cups flour, yeast, 1 tablespoon sugar, and 1 teaspoon salt in a large mixer bowl.

Mix well.

Add warm water and vegetable oil to the flour mixture.

Blend at low speed until moistened.

Beat at medium speed for 3 minutes.

Gradually stir in the remaining flour by hand to form a firm dough.

Knead the dough on a floured surface for 5-8 minutes, adding flour as needed until smooth and elastic.

Place the dough in a greased bowl, turning to coat the top.

Cover the bowl and let it rise in a warm place for about 40 minutes (or 20 minutes for Quick Rise yeast).

Prepare the onion topping by sautéing sliced onions in butter in a small skillet until softened.

Stir in 1/3 teaspoon sugar and 1/8 teaspoon salt into the sautéed onions.

Punch down the risen dough.

Shape the dough into a ball on a lightly floured surface.

Place the ball on a greased cookie sheet.

Flatten the dough into a 10-inch circle.

Cut a circle in the dough about 1 inch from the edge, almost through to the cookie sheet, using a table knife.

Prick the center of the dough with a fork.

Spread the onion topping evenly over the pricked dough.

Cover the dough and let it rise in a warm place for about 30 minutes (or 15 minutes for Quick Rise yeast).

Bake in a preheated oven at 375°F (190°C) for 25-30 minutes, or until golden brown.