Preheat the oven to 375°F. Line a baking sheet with parchment paper.
In a large bowl, combine the ground beef, breadcrumbs, cheddar cheese, Parmesan cheese, milk, egg, garlic powder, onion powder, salt, black pepper, and Italian seasoning. Mix until just combined; do not overmix.
Using your hands, form the mixture into small balls, about 1.5 inches in diameter, and place them on the prepared baking sheet.
Bake in the preheated oven for 20-25 minutes, or until the meatloaf bites are cooked through and reach an internal temperature of 160°F.
Serve warm with marinara sauce for dipping.