For the tomato sauce:
1) Heat the oil over a medium high heat in a large saucepan. Add the onion and garlic and saute until soft and translucent, about 5 to 10 minutes.
2) Add the celery and carrot and season with salt and pepper. Saute until all the vegetables are soft, about 5-10 minutes.
3) Add the tomatoes and bay leaves and simmer uncovered on a low heat for one hour or until thick. Remove the bay leaves and check for seasoning. If the sauce still tastes acidic, add unsalted butter, one tablespoon at a time, to round out the flavours.
4) Put half the tomato sauce into the bowl of a food processor and process until smooth. Repeat with the remaining tomato sauce.
5) If not using all the sauce, allow it to cool completely and pour portions into freezer plastic bags. It will freeze up to six months.
Yield: About 1.5 litres.
For the penne with vodka sauce:
1) Place the tomato sauce and vodka in a heavy large frying pan and simmer over a low heat until the mixture reduces by 1/4, stirring often, about 20 minutes.
2) Stir the cream into the tomato and vodka sauce. Simmer over low heat until the sauce is heated through. Stir in the Parmesan cheese until melted and well blended.
3) Meanwhile, cook the pasta in a large pan of boiling salted water until al dente (tender but still firm to the bite), stirring occasionally, about 8 minutes. Drain the pasta and transfer it to the pan with the sauce, and toss to coat. Serve immediately.