Step 1

Preheat oven to 350°F. Line a baking sheet with aluminum foil and lightly coat with cooking spray.

Step 2

In a large bowl, mix together beef, egg, milk, parmesan cheese, mozzarella cheese, parsley, garlic powder, minced onion, oregano, salt, and pepper with your hands.

Step 3

Shape into 12 decent sized meatballs. Place on the prepared baking sheet. Bake for 35-40 minutes.

Step 4

Pour marinara sauce into the slow cooker and add the meatballs. Cook on HIGH for 3 hours or LOW for 4 1/2 hours.

Step 5

Garnish with shaved parmesan cheese, to serve.