Bring a large pot of salted water to a rolling boil. Add pasta and cook according to package instructions until al dente, usually 8-10 minutes. Reserve ½ to ⅓ cup of pasta water before draining.

In a large skillet, melt 2 tbsp of unsalted butter over medium heat. Add cherry tomatoes, seasoning with salt and pepper. Cook for 5 minutes until tomatoes are soft.

Stir in minced garlic and red pepper flakes, cooking for another 30 seconds until fragrant without browning.

Pour in reserved pasta water while stirring, then mix in grated parmesan cheese until melted. Finally, add mascarpone cheese and stir until creamy.

Toss the cooked pasta with the sauce in the skillet, adding torn basil leaves and adjusting with more pasta water if needed. Serve immediately, drizzled with basil oil if desired.