Cook the linguine in salted boiling water until just tender. Before draining, reserve ½ cup of the pasta water, then set the pasta aside.
Melt the butter in a large skillet over medium-high heat. Add the ground beef and cook until browned, breaking it into crumbles as it cooks. Drain any excess grease.
Stir in the diced onion and cook until softened. Add the garlic, tomato paste, and Italian seasoning, mixing until everything is well combined.
Pour in the heavy cream and let the sauce warm for about 3 minutes, stirring occasionally.
Add the Parmesan followed by the mozzarella, stirring until the cheeses melt into a smooth, creamy sauce. Mix in a little reserved pasta water if needed for a silky consistency.Buy Artisan Cheese
Add the cooked linguine to the skillet and gently work it through the sauce until every strand is coated.
Season with the salt and black pepper, then serve while hot.