Meanwhile, in 10-inch skillet over medium heat, cook bacon until crisp. Drain on paper towels; crumble. Reserve 1 teaspoon bacon drippings in skillet. Add onion; cook over medium heat 1 to 2 minutes, stirring frequently, or until tender. Remove from heat; stir in Alfredo sauce, remaining 1 teaspoon Worcestershire sauce and bacon. Spoon about 2 teaspoons bacon mixture onto each round; sprinkle with Gruyère cheese.