Preheat your oven to 400°F (200°C). Gather your baking sheet and line it with parchment paper.

In a large mixing bowl, add the ground beef, breadcrumbs, Parmesan cheese, onion, garlic, parsley, and salt and pepper. Mix gently until just combined.

With damp hands, scoop out portions of the meat mixture and roll them into 1.5-inch meatballs. Place on the prepared baking sheet.

Bake in the preheated oven for 18-20 minutes until golden brown and cooked to an internal temperature of 165°F (74°C).

For optional flavor, transfer baked meatballs to a saucepan and simmer in marinara sauce for 15-20 minutes.