Preheat your oven to 375°F and prepare a 12-cup muffin tin by greasing it well or lining with paper cups.

Whisk together the flour, baking powder, salt, and garlic powder in a large bowl until well combined.

In a separate bowl, combine the milk, melted butter, and eggs, whisking until everything is well blended.

Pour the wet ingredients into the dry ingredients and stir just until the flour disappears, being careful not to overmix.

Fold in the mozzarella, pepperoni, sausage, bacon bits, Parmesan, oregano, and basil, stirring gently until distributed. Add red pepper flakes if desired.

Divide the batter among the 12 muffin cups, filling each about two-thirds full.

Bake for 18 to 22 minutes, or until a toothpick inserted into the center comes out clean or with just a few moist crumbs.

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