Bring a large pot of salted water to a rolling boil (about 2 tablespoons salt for 4 quarts water).

While water heats, place a large 12-inch skillet over medium heat. Add olive oil and swirl to coat.

Add sliced garlic and red pepper flakes to the oil. Cook, stirring constantly, until garlic is fragrant and just starting to turn golden at the edges — about 45 seconds. Do not let it brown.

Pour in the crushed tomatoes. Stir in salt and black pepper. Bring to a simmer, then reduce heat to low. Let it bubble gently for 15 minutes, stirring occasionally. The sauce will thicken and darken slightly.

Meanwhile, add pasta to the boiling water. Cook according to package directions until al dente (usually 8-10 minutes). Reserve 1 cup of pasta water before draining.

Drain pasta (do not rinse). Add it directly to the skillet with the sauce. Toss well, adding reserved pasta water a splash at a time if the sauce seems too thick. You want it to coat each strand with a glossy sheen.

Remove from heat. Stir in fresh basil. Taste and adjust salt if needed.

Serve immediately, topped with grated Parmesan if desired.