For dough, in a large bowl, soften yeast in 1/4 cup warm water. In another bowl, stir together the flour, baking powder, and salt.
Stir 1/4 cup warm water, the shortening and sugar into the softened yeast. Add the flour mixture, stirring to combine. Form into a ball.
On a lightly floured surface, roll the dough into a 12-inch circle. Fit into a 12-inch pizza pan. Build up edges slightly.** Bake crust in a 375 degree F oven for 9 minutes.
For sauce, stir together the tomato sauce, finely chopped onion, garlic, oregano, basil, and black pepper.
Spread sauce on prebaked crust. Sprinkle with Parmesan cheese. Arrange vegetables over sauce. Sprinkle with mozzarella and cheddar cheeses.
Bake in the 375 degree F oven about 20 minutes or until vegetables are hot and cheeses are melted. Remove from oven; sprinkle with chopped tomato. Makes 4 servings.
If you like, snip the edge of the pizza crust with kitchen scissors for a decorative edge.
If you like, slice the tomato and arrange it with other fresh vegetables on the crust instead of chopping the tomato and sprinkling it over the pizza.
