Preheat your oven to 400°F (200°C).

Combine your ingredients in a large bowl. Mix together the ground beef, breadcrumbs, Parmesan cheese, minced garlic, parsley, egg, salt, pepper, and Calabrian chili peppers gently until just combined.

Form the mixture into meatballs, about 1.5 tablespoons each, and place them on a parchment-lined baking sheet.

Bake for 20-25 minutes, until golden brown and the internal temperature reaches 160°F (70°C).

Heat your favorite marinara sauce and add the baked meatballs, letting them simmer for about 10 minutes.

Serve hot over spaghetti or with crusty bread.