Enchilada Sauce (from Cook's Illustrated)

1 medium onion , chopped fine

1/2 teaspoon vegetable oil

3 medium cloves garlic , minced

3 tablespoons chili powder

2 teaspoons ground cumin

2 teaspoons sugar

2 cans (8 ounces each) tomato sauce

1 cup water

Combine the onion, oil, and 1/2 teaspoon salt in a large saucepan. Cover and cook over medium-low heat, stirring often, until the onions have softened, 8 to 10 minutes. Stir in the garlic, chili powder, cumin, and sugar, and cook until fragrant, about 30 seconds. Stir in the tomato sauce and water, bring to a simmer, and cook until slightly thickened, about 5 minutes.