Ingredients

• 2 tablespoons olive oil
• 2 medium onions, peeled and coarsely chopped
• 3 (1 pound. 12 ounce) cans imported Italian plum tomatoes
• 1 bunch fresh basil
• Pinch of crushed red pepper flakes
• 1 tablespoon unsalted butter
• 2 pounds spaghetti

Instructions

1. Heat the olive oil over medium-high heat in a heavy saucepan. Saute the onions in it for 5 to 10 minutes or until transparent and just starting to brown.
2. Using a knife, cut the tomatoes coarsely inside their cans. Drain off the juice and reserve.
3. Add the tomatoes to the saucepan, along with a dozen basil leaves, very coarsely chopped. Season with salt and red pepper flakes to taste. Let the sauce come to a boil, then lower heat, simmer for 45 minutes. It should have a medium-thick consistency; keep adding back some of the reserved tomato liquid to maintain the correct consistency.
4. While the sauce is cooking, boil the spaghetti in a large amount of salted water.
5. When ready to serve, add another dozen very coarsely chopped basil leaves to the sauce, and whisk in the butter. Drain the cooked spaghetti in a colander, draining all water from the pasta cooking pot, then return the spaghetti to the pot. Add about 2/3 of the sauce to it, or just enough to lightly coat the spaghetti with sauce. Stir well for one minute over medium heat. Divide spaghetti among eight bowls, placing a few small basil leaves on each spaghetti bowl. Top each with a few tablespoons of sauce. Serve immediately. Pass freshly grated Parmigiano-Reggiano if desired.