Bring a large saucepan of generously salted water to a rolling boil. Add the spaghetti and cook until just al dente, about 8 minutes, stirring occasionally. Drain and set aside, reserving a cup of pasta water.
While the pasta cooks, rinse and halve or tear the tomatoes into bite-sized pieces. Peel and finely mince the garlic cloves. Tear the basil leaves into small pieces to release their aroma.
Heat the olive oil in a wide skillet over medium heat until it shimmers and starts to smell fragrant, about 30 seconds. Add the minced garlic and sauté gently until just golden and fragrant, about 30 seconds to 1 minute. Be careful not to burn it.
Add the chopped tomatoes to the skillet. Cook gently, pressing them slightly with the back of a spoon, until they soften and release their juices, about 3-4 minutes. The tomatoes should shimmer and bubble slightly, creating a glossy, fragrant sauce.
Taste the sauce and season with salt, black pepper, and chili flakes if using. If the sauce seems too thick, stir in a splash of reserved pasta water to loosen and enhance the glossiness.
Drain the cooked spaghetti and immediately transfer it into the skillet with the tomato sauce. Toss gently with a wooden spoon to coat all the pasta evenly. Add torn basil leaves and toss again until fragrant and vibrant, about 30 seconds.
Remove from heat and drizzle with a little more olive oil if desired. Let sit for a minute to meld flavors and cool slightly. The dish should be glossy, fragrant, and vibrant with fresh basil and juicy tomatoes.
Serve immediately, garnished with extra basil if desired. Enjoy this bright, simple, and satisfying bowl of summer-inspired spaghetti.
