Cook the bowtie pasta according to package instructions until al dente. Reserve 1/2 cup of pasta cooking water, then drain and set aside.

In a large skillet, heat olive oil over medium heat. Add ground beef and cook, breaking it apart, until browned (about 5–7 minutes).

Add chopped onion and garlic to the skillet. Cook until the onion is soft and translucent, about 3 minutes. Stir in Italian seasoning and red pepper flakes (if using), then season with salt and pepper. Remove beef mixture from the skillet and set aside.

In the same skillet, melt butter over medium heat. Add the minced garlic and sauté for 1 minute until fragrant.

Whisk in the flour and cook for 1–2 minutes to form a roux. Gradually whisk in the milk to avoid lumps.

Simmer gently until the sauce begins to thicken, about 3 minutes.

Reduce heat to low. Stir in mozzarella and Parmesan until melted and smooth.

Return pasta and beef mixture to the skillet and toss everything together to coat evenly. If the sauce is too thick, add a splash of the reserved pasta water.

Serve warm, garnished with chopped parsley and extra Parmesan if desired.