Meanwhile, in large skillet, cook chopped bacon over medium-high heat until fat is rendered and bacon is almost crispy, 3 to 4 minutes. Add mushroom slices; cook until softened, about 3 minutes. Sprinkle with flour; cook, stirring, 1 minute. Pour in beer and Worcestershire. Reduce heat to medium; simmer, stirring occasionally, until some of liquid evaporates, 4 to 5 minutes.