Bring a large pot of salted water to boil. Add the pasta. Cook according to package instructions, then drain.
As the pasta cooks, heat the butter in a large, deep skillet or heavy bottomed pot over medium heat. When the butter is sizzling, add the tomatoes. Cover and cook for 10 minutes, stirring a few times. Uncover and add the garlic, salt, and oregano. Stir the sauce and continue to cook, uncovered, for 2-3 more min. The tomatoes should be collapsed and the sauce should be juicy.
Stir in the cooked spaghetti. Heat everything through for about a minute. Add additional salt and black pepper to taste. Serve immediately, with fresh, torn basil leaves on top of each serving.
Notes
Leftover pasta will keep for up to three days in an airtight container in the fridge.