1. In a large, heavy skillet cook bacon over medium heat until crisp. Transfer to paper towels; set aside.
2. Add olive oil to the same skillet. Cook and stir mushrooms in hot oil over medium heat for 1 to 2 minutes or until mushrooms just begin to brown. Cover and cook mushrooms for 8 minutes or until tender, stirring occasionally. Stir in cooked bacon and mustard; heat through. To serve, sprinkle parsley over mushrooms. Makes 4 side-dish servings.