3 medium leeks (white and pale green parts only) halved cleaned and cut into 1 inch peices
3 tablespoons unsalted butter
1 lb carrots, cut diagonally into 1 1/4-inch pieces
1 1/4 cups water
2-4 tablespoons vinegar (balsamic, red wine, sherry, or white wine)
Sauté leeks in butter with 1 teaspoon salt and 1/2 teaspoon pepper in a 12-inch heavy skillet over medium-high heat until softened, 5 to 6 minutes.
Stir in carrots, water, and vinegar. Cook, covered, over medium-high heat until carrots are tender, 20 to 25 minutes.
Boil, uncovered, until liquid has evaporated, 3 to 5 minutes.