01 - Bring a large pot of salted water to a boil. Cook the pasta according to package instructions until al dente. Reserve 1/2 cup of pasta water, then drain.
02 - While the pasta cooks, heat olive oil in a large skillet over medium heat. Add garlic and chili, sautéing for 1-2 minutes until fragrant but not browned.
03 - Add diced tomatoes, sugar, salt, and black pepper to the skillet. Simmer uncovered for 10-12 minutes, stirring occasionally, until the sauce thickens.
04 - Taste and adjust seasoning as needed. Stir in half the torn basil leaves.
05 - Add drained pasta to the sauce, tossing to coat evenly. Add reserved pasta water gradually if the sauce requires loosening.
06 - Remove from heat. Stir in grated Parmesan and remaining basil leaves. Drizzle with extra virgin olive oil. Serve immediately with extra Parmesan and a sprinkle of chili flakes if desired.