Tomato Sauce

A three-line convenience sauce from the era when canned soup first became a pantry staple. The proportions work, but the original assumes you know what a white sauce is and that the vegetables get cooked.

• The hinge: cook the vegetables firstSweat the diced pepper and onion in a little butter until soft before adding the soup, or they stay raw and crunchy in a sauce meant to be smooth. Five to seven minutes over medium heat is enough.
• Use the soup undilutedCondensed tomato soup is meant to be thinned with a can of water for serving as soup. Here it functions as a tomato base, so add it straight from the can; the white sauce is the only liquid it needs.
• White sauceA simple white sauce of the period: 1 tablespoon butter, 1 tablespoon flour and 1 cup milk, cooked until it coats a spoon. (By the usual period scale this is a thin sauce; a medium one took about two tablespoons each.) You need only half a cup, so make a small batch or use leftover from another dish.
• "A little onion"Genuinely unspecified. About a tablespoon of finely minced onion suits a can of soup without dominating the tomato.
• SaltCondensed soup carries a great deal of sodium, then and now. Season at the end, after the white sauce has diluted it, rather than at the start.
• Keep it below a boilOnce the milk-based white sauce goes in, hold the pan at a bare simmer. A hard boil in an acidic tomato base will curdle the milk and leave the sauce grainy.
• Yield and useRoughly a cup and a half to two cups, enough for about four servings.