Rinse, peel, and chop 1 medium carrot into sticks with a sharp knife, then cut it into small dice.
Rinse and chop 1 rib celery into sticks, then cut it into small dice.
Peel 1 medium to large onion, cut it in half, and then finely chop it into small dice.
Heat 2 tablespoons extra virgin olive oil in a large pan, skillet, or pot, then add the chopped vegetables and ¼ teaspoon salt.
Cook gently on medium to medium-low heat for 5 to 20 minutes, depending on how much time you have. Stir often with a wooden spoon.The longer the vegetables cook, the more flavor they release.
The vegetables should not brown or caramelize. They should slowly become tender and translucent, releasing their sweetness.Use soffritto as a flavor base for other preparations. For ideas, see "Recipes with Soffritto" chapter linked in the notes below.