Bring a large pot of salted water to a boil over high heat.

Add the spaghetti to the boiling water in the pot and cook according to the package directions until tender but firm to the bite.

While the pasta cooks, heat the olive oil and 2 tablespoons of the butter in a large skillet over medium heat.

Add the sliced garlic and red pepper flakes to the skillet, cooking for about 1 minute until the garlic is fragrant but not browned.

Stir in the tomato paste and the halved cherry tomatoes, cooking for 3 to 4 minutes until the tomatoes begin to soften and release their juices.

Before draining the pasta, carefully scoop out 1/2 cup of the starchy pasta cooking water and set it aside.

Drain the spaghetti and add it directly into the skillet with the tomato mixture.

Add the remaining 2 tablespoons of butter and a splash of the reserved pasta water, tossing everything together over low heat until the sauce is glossy and coats the noodles.

Remove the skillet from the heat and stir in the grated Parmesan cheese and fresh parsley.

Serve immediately, adding more salt or pepper if needed.