Preheat the oven to 375°F and line a baking sheet with parchment paper.
In a medium mixing bowl, whisk together the flour, baking powder, and salt.
Add the Greek yogurt and stir until a soft, shaggy dough forms.
Transfer the dough to a lightly floured surface. Gently knead it a few times until smooth, adding a small amount of flour if the dough is too sticky.
Divide the dough into 8 equal portions. Flatten each piece into a small circle.
Add approximately 1½ tablespoons of mozzarella cheese and 3 chopped pepperoni slices to the center of each piece.
Fold the dough around the filling and pinch the edges tightly closed. Shape it into a ball and place it seam-side down on the prepared baking sheet.
Brush the tops with melted butter and sprinkle with Italian seasoning.
Bake for 18–22 minutes, or until the pizza bites are puffed and golden brown.
Cool for about 5 minutes before serving warm with pizza sauce.