Skip Lombardi suggests that soffrito can be made in advance and stored in the fridge for up to a month. Sure, but why?

For certain, it will save time when you come to make the soffrito-based recipe, but you still have to make it sometime. OK, so you can make a big batch all in one go. But the effort (as opposed to the time) in making soffrito is in chopping the ingredients, and the more there are, the longer it takes. Skip neatly gets round this this with a food processor: pulse, pulse. pulse, and there you go. Easy. But I have generally found that food processors pulverize onions rather than chop them, releasing bitter juices that do not easily cook out.

Anyway, for me, part of the magic of making a dish that calls for soffrito is preparing the ingredients, letting them fry gently whilst infusing the kitchen with a lovely aroma as one prepares the rest of the meal...