Preheat oven to 400°F. Line a baking sheet with parchment paper; set aside.

Using a large bowl, combine the bread crumbs and milk; let soak for 5 minutes.

Meanwhile, add the olive oil to a medium frying pan and place over medium-high heat. Once hot, add the diced onions and cook for 5-6 minutes, or until onions begin to soften.

Transfer onions into bowl with bread crumbs. Add all of the remaining meatball ingredients (beef, pork, egg, parsley, garlic, salt, pepper, oregano, red pepper and Parmesan cheese). Mix until just combined. (Tip: Take care not to overmix or the meatball may be tough.)

Divide mixture into 12 equal pieces. Place meatballs 1” apart on prepared baking sheet.

Bake for 23-27 minutes, or until meatballs are fully cooked.

Spray muffin tin with nonstick spray; set aside.

Divide the pizza dough into 12 equal pieces (~2 oz. each). Roll each piece into a 3”x3” circle.

Cut each slice of cheese into 4 pieces. Place one piece of cheese in center of each piece of dough. Place a meatball on top of cheese and then lay another piece of cheese on top of meatball.

Wrap dough around meatball and cheese, pinching edges to seal; place into prepared muffin tin.

Using a small bowl, whisk together olive oil, Parmesan cheese, garlic, Italian seasonings and kosher salt. Brush this mixture evenly on top of each meatball.

Bake at 400°F for 18-20 minutes, or until golden brown.

{Optional} Top each meatball with a spoonful of marinara sauce and a bit of shredded mozzarella cheese. Continue baking for 2-3 minutes, or until cheese has melted.

Serve with marinara sauce for dipping.