Preheat your oven to 375°F (190°C).
In a large mixing bowl, combine flour, baking powder, salt, and oregano.
Add the shredded mozzarella and diced pepperoni to the dry mixture.
In a separate bowl, whisk together the milk, egg, and olive oil until well combined.
Pour the wet mixture into the dry ingredients and stir until just combined.
Spray a baking tray with cooking spray.
Scoop portions of the dough onto the prepared tray, spacing them about 2 inches apart.
Bake in the preheated oven for 15-20 minutes or until golden brown.
Remove from the oven and let cool slightly before serving.
Enjoy your cheesy pepperoni pizza puffs while they're warm!