In a large bowl, beat eggs, milk and Parmesan. Season with salt and pepper. Add leftover spaghetti and combine well.
In a large 10-inch non-stick skillet, heat extra-virgin olive oil over medium heat. Add spaghetti and egg mixture, spreading evenly and pressing down in pan. Cook until golden brown, about 8 minutes. Carefully invert onto plate, add a little more oil to the pan, and slide mixure back into skillet and cook the other side for 6 minutes. Turn out onto serving platter and cut into wedges and serve warm.
In a large pot, bring 6 quarts of salted water to a boil. When water comes to a boil, add pasta, stirring constantly for the first minute to help prevent spaghetti from sticking together. Cook until al dente, about 8 to 10 minutes.
In a large saute pan, heat oil. When almost smoking, add olives and red pepper flakes. Saute for 3 minutes over medium high heat. Reduce heat to low and carefully pour in tomato sauce and simmer for 10 minutes.
Drain pasta in a colander, reserving 1/4 cup pasta water. Add pasta to the sauce and toss to coat completely. Add pasta water if you need to thin out the sauce a bit. Plate pasta and sprinkle with Parmesan cheese and basil.
In a large casserole pot, heat oil over medium high heat. Add onion and garlic and saute until soft and translucent, about 5 to 10 minutes. Add celery and carrots and season with salt and pepper. Saute until all the vegetables are soft, about 5 to 10 minutes. Add tomatoes and bay leaves and simmer uncovered on low heat for 1 hour or until thick. Remove bay leaves and check for seasoning. If sauce still tastes acidic, add unsalted butter, 1 tablespoon at a time to round out the flavors.
Add 1/2 the tomato sauce into the bowl of a food processor. Process until smooth. Continue with remaining tomato sauce.
If not using all the sauce, allow it to cool completely and pour 1 to 2 cup portions into freezer plastic bags. This will freeze up to 6 months.