Preheat your oven to 400°F (200°C) and grease a 9-inch round pizza pan or baking sheet.

In a mixing bowl, combine the flour, baking powder, and salt. Mix well.

In another bowl, whisk together the milk, egg, and olive oil until smooth.

Gradually add the wet ingredients to the dry ingredients, stirring until just combined.

Spread the dough evenly onto the prepared pizza pan, pressing it out to the edges.

Sprinkle the shredded mozzarella cheese over the dough, followed by the cooked sausage, bell peppers, onions, black pepper, garlic powder, oregano, and red pepper flakes if using.

Bake in the preheated oven for 15-20 minutes, or until the cheese is bubbly and the crust is golden brown.

Remove from the oven and let it cool for a few minutes before slicing. Garnish with fresh parsley if desired.