1. Preheat the oven to 350F. Slice the bread in half horizontally, then in half crosswise to form 4 slices; place on a baking sheet.

2. In a small saucepan, bring the pasta sauce and red pepper flakes to a boil over medium heat. Remove from the heat.

3. Spread the sauce evenly over the bread slices. Sprinkle 1/2 cup mozzarella and one-fourth of the oregano over each slice. Bake just until the cheese melts, about 10 minutes.  Transfer the pizzas to a serving platter and serve.

Variations
Let individual cravings be your guide and add any toppings before baking: sliced olives, sautéed bell pepper strips, sautéed mushrooms, or pepperoni slices.