Juice lemon to measure 2 Tablespoons juice; place in small bowl. Add mustard, worcestershire sauce, garlic and black pepper; whisk until blended. Add mayonnaise; whisk until smooth.
While continually whisking, add oil to mayonnaise in a thin, steady stream. Continue whisking until blended; stir in parmesan cheese. Cover; refrigerate until ready to serve. Store dressing covered in refrigerator up to 2 weeks.