Preheat your oven to 375°F (190°C) and grease a muffin tin with cooking spray or olive oil.

In a large mixing bowl, whisk together the flour, baking powder, salt, garlic powder, and oregano until well combined.

Stir in the mozzarella and Parmesan cheeses, mixing until the cheese is evenly distributed throughout the dry ingredients.

In a separate bowl, combine the milk, egg, and olive oil. Whisk until smooth.

Pour the wet ingredients into the dry ingredients and mix until just combined. Do not overmix.

Fold in the pizza sauce, cooked sausage, and any optional vegetables like bell peppers or mushrooms.

Divide the batter evenly among the muffin cups, filling each about ¾ full.

Bake in the preheated oven for 20-25 minutes, or until the muffins are golden brown and a toothpick inserted into the center comes out clean.

Allow the muffins to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.