Cook pasta according to package directions. In a large skillet, melt the butter over medium heat; add onion and garlic; cook and stir until onion is soft. Add asparagus; cook and stir for 2 minutes. Add wine (or broth) and lemon juice; cook for 1 minute. Season with pepper to taste. Remove from heat. In a large bowl, toss hot pasta, Parmesan cheese and asparagus mixture. Sprinkle with Mozzarella cheese before serving.