Preheat oven to 375°. Heat oil in medium skillet over medium heat. Add onion and cook, stirring frequently, until soft, about 5 minutes. Add garlic, 1/4 teaspoon salt, and 1/4 teaspoon pepper; cook, stirring, 1 minute. Stir in Worcestershire sauce, broth, and 1 tablespoon ketchup; transfer mixture to a large bowl, and cool.