Cook the Pasta: Bring a large pot of heavily salted water to a boil. Add the penne and cook until al dente, about 1 minute less than package directions. Before draining, reserve at least 1 cup of the starchy pasta water.

Infuse the Oil: While the pasta cooks, heat the olive oil in a large skillet over low heat. Add the sliced garlic and crushed red pepper flakes. Cook gently for 2-3 minutes, swirling the pan, until the garlic is fragrant and barely golden. Do not let it brown.

Build the Sauce: Crush the whole tomatoes by hand into the skillet. Add the optional tomato paste and season with salt and pepper. Increase the heat to bring to a simmer, then reduce to maintain a gentle bubble. Cook for 10-15 minutes, allowing the sauce to thicken slightly.

Combine Pasta and Sauce: Drain the pasta and immediately add it to the skillet with the sauce.

Emulsify: Increase the heat to medium. Add a splash (about 1/4 cup) of the reserved pasta water and toss the pasta vigorously. The starch in the water will help the sauce cling to the pasta, creating a glossy, emulsified coating. Continue adding splashes of pasta water and tossing until the pasta is perfectly coated.

Serve: Serve immediately, garnished with fresh basil or parsley and optional grated cheese.