Stewed tomatoes are very simple to prepare. I just blanch the tomatoes and slip the skin off then chop them into large chunks.
While I am doing that I have the chopped peppers, onions and zucchini sauteing in olive oil- I've already run them through the food processor.
I add in some garlic.
Did I mention I was lucky enough to get to buy some gorgeous local garlic...and not just regular garlic - homelearner garlic! ;-) My family went for a long time this year without any garlic because we ran out of last year's garlic too early and I do not wish to buy the garlic from China that they are selling in our grocery stores. Happily we had a supply of roasted garlic powder made by a generous friend out of last year's garlic and so we were still able to satisfy our taste for local garlic with that (And yes, roasted garlic powder is as delicious as it sounds - we call it "gold" around here and spoon it out very carefully).