Preheat the oven to 400°F (200°C) and line a baking sheet with parchment paper.
In a mixing bowl, combine the shredded mozzarella and cheddar cheeses.
In another bowl, whisk together the flour, baking powder, garlic powder, onion powder, and salt.
Mix the dry ingredients into the cheese until well incorporated.
In a separate bowl, whisk the egg and milk together. Pour this mixture into the cheese and flour mixture, stirring until a dough forms.
Using your hands, shape small balls (about 1 inch in diameter) from the dough and place them on the prepared baking sheet.
Bake the cheesy balls in the preheated oven for 15-20 minutes or until golden brown on the outside.
If you prefer frying them, heat oil in a frying pan over medium heat and fry the balls until golden, about 3-4 minutes on each side.
Remove from the oven or oil and let them cool slightly before serving.