01 - Preheat oven to 375°F. Line a baking sheet with parchment paper.
02 - In a large bowl, combine ground beef, breadcrumbs, Parmesan cheese, egg, minced garlic, milk, oregano, basil, salt, and pepper. Mix until just combined, being careful not to overwork the mixture.
03 - Form the mixture into 24 small meatballs, each approximately 1 inch in diameter.
04 - Arrange meatballs on the prepared baking sheet and bake for 12 to 15 minutes until cooked through.
05 - While meatballs are baking, lightly grease a mini muffin tin. Flatten each biscuit or roll and press into the muffin cups to form a shell.
06 - Place one baked meatball in each dough cup. Top each with 2 teaspoons marinara sauce and a generous sprinkle of mozzarella cheese.
07 - Brush the edges of the dough with melted butter.
08 - Bake at 375°F for 10 to 12 minutes until the dough is golden and cheese is melted.
09 - Remove from oven and let cool slightly. Garnish with chopped parsley if desired. Serve warm.