Preheat the oven to 400°F. Line a baking sheet with parchment paper.

In a large bowl, combine ground beef, breadcrumbs, Parmesan cheese, parsley, egg, minced garlic, salt, pepper, and Italian seasoning. Mix until just combined.

Form the mixture into 1-inch meatballs and place them on the prepared baking sheet. Bake for 20-25 minutes or until cooked through.

While the meatballs are baking, cook the linguine according to package instructions. Drain and set aside.

In a large skillet over medium heat, melt the butter. Add minced garlic and sauté for 1-2 minutes until fragrant.

Stir in lemon juice and red pepper flakes (if using). Add the cooked meatballs to the skillet and toss to coat in the garlic butter sauce. Cook for an additional 2-3 minutes.

In a separate saucepan, combine heavy cream and Parmesan cheese over medium heat. Stir until the cheese is melted and the sauce is creamy. Season with salt and pepper to taste.

Toss the cooked linguine in the creamy Parmesan sauce until well coated.

Serve the creamy linguine topped with garlic butter meatballs and garnish with chopped parsley.