Bring a large pot of salted water to a rolling boil. Add the bow tie pasta and cook until al dente, about 8-10 minutes. Drain and reserve a cup of pasta water.

In a large skillet, heat a drizzle of olive oil over medium heat. Add the diced onion and sauté for 3-4 minutes until soft and translucent.

Stir in the minced garlic and sauté for an additional minute until fragrant, being careful not to burn it.

Crumble the Italian sausage into the skillet and cook for 5-7 minutes until browned and cooked through.

Pour in the diced tomatoes, dried basil, oregano, salt, and pepper. Reduce heat and let simmer for about 5 minutes.

Add the drained pasta to the skillet. Toss everything together until well-coated with sauce, adding reserved pasta water if necessary.

Remove from heat and sprinkle with mozzarella and Parmesan cheese. Cover for 2-3 minutes to melt the cheeses.

Serve hot, garnished with fresh basil leaves.