Bring a large stock pot of water to a boil. Season generously with salt. While water is coming to a boil, heat olive oil in a sauté pan on medium-low heat. Add the garlic, onion, and a small pinch of chili flake. Cook, stirring frequently, until the onion has softened and become translucent, about 4 minutes. Season with a small pinch of sea salt.
Add the cherry tomatoes. Cook on medium-low heat for 5-10 minutes, until the sauce has thickened and the tomatoes have started to breakdown. Taste and season with salt and pepper.
Cook the pasta in the boiling water until al dente. Scoop hot pasta directly into the sauté pan with the sauce. Add the basil leaves and toss until pasta is coated. Add a little pasta water if necessary. Taste and season with salt and pepper. Scoop pasta into individual bowls. Top with freshly grated Parmigiano Reggiano.