01 - Bring a large pot of salted water to a boil. Cook the penne according to package directions until al dente. Reserve 0.5 cup of pasta water, then drain.
02 - While pasta cooks, heat olive oil in a large skillet over medium heat. Add minced garlic and onion; sauté for 2–3 minutes until softened and fragrant.
03 - Stir in crushed tomatoes, sugar, red pepper flakes, salt, and black pepper. Simmer for 10–12 minutes, stirring occasionally to develop flavors.
04 - Add drained penne to the skillet with sauce. Toss thoroughly, incorporating a splash of reserved pasta water if needed for a silky consistency.
05 - Gently fold in ricotta cheese, half the basil, and grated Parmesan. Cook for 1–2 minutes until everything is heated through.
06 - Divide among serving plates. Top with remaining basil and additional Parmesan as desired.