Bell Pepper Meatball Sandwiches

Preheat oven to 350°F. In a small bowl, soak the bread in the milk.

In a large bowl, combine beef, bread, parsley, Parmesan, egg, garlic, salt, and red pepper flakes. Mix until just combined and form into 16 balls. If the mixture is too loose you can add a little bit of bread crumbs.

In a skillet over medium-high heat, add 1 tablespoon oil. Add meatballs and cook, turning occasionally, until seared on all sides, about 10 minutes. Add marinara sauce to skillet and toss to combine. Cover skillet with lid and simmer until meatballs have cooked through completely, about 10 minutes more.

Place bell peppers cut side up on a large rimmed baking sheet and drizzle with remaining olive oil. Top 4 halves with mozzarella slices. Bake until cheese has melted and bell peppers are warmed through and slightly softened.

Add meatballs on top of the bell pepper halves with cheese and sprinkle with more Parmesan, if using. Place remaining bell pepper halves on top and serve.