Cook the pasta: Add the spaghetti to the boiling water and cook until it is nearly tender but still has a firm bite, usually about 2 minutes less than the package directions.

Start the sauce: While the pasta cooks, place a large skillet over medium heat and add the olive oil and butter.

Sauté the aromatics: Once the butter has melted, add the sliced garlic and red pepper flakes to the skillet, cooking for about 1 minute until the garlic is fragrant and just beginning to turn golden.

Brown the paste: Stir in the entire 6-ounce can of tomato paste, mashing it into the oil and butter with a wooden spoon.

Develop the flavor: Continue cooking the tomato paste for 5 to 7 minutes, stirring frequently, until it changes from bright red to a deep brick-red color and begins to smell toasted.

Save the pasta water: Before draining the pasta, carefully scoop out about 2 cups of the cloudy pasta water and set it aside.

Combine: Drain the pasta and add it directly to the skillet with the browned tomato paste.

Glaze the pasta: Pour in 1 cup of the reserved pasta water and toss the noodles vigorously over medium heat until the paste transforms into a smooth, glossy sauce that clings to the pasta.

Season: Add more pasta water a splash at a time if the sauce looks too thick, then stir in the salt, black pepper, and half of the Parmesan cheese.

Finish and serve: Divide the pasta into bowls and top with the remaining Parmesan and the torn fresh basil before serving.