1 pound plum tomatoes, stem ends removed
2 tablespoons unsalted butter
1 1/2 teaspoons salt, or to taste
1/2 teaspoon freshly ground pepper, or to taste
1 tablespoon plus 2 teaspoons white wine vinegar
2 tablespoons light brown sugar, firmly packed
Coarsely chop tomatoes keeping skins and seeds intact.
In a medium-sized sautÃ© pan melt butter over medium-high heat. Add tomatoes and season with salt and pepper. Cook about 5 minutes until tomatoes have softened.
Add white wine vinegar and light brown sugar and cook 5 minutes or so longer until tomatoes are very soft and their juice has thickened. Cool and serve slightly warm or at room temperature.
Tomato jam can be made ahead and refrigerated in an airtight container for up to 5 days.