Bring A Large Pot Of Lightly Salted Water To A Boil. Add Penne And Cook Until Al Dente, 8 To 10 Minutes; Drain. Meanwhile, Heat The Olive Oil In A Large Skillet Over Medium Heat. Stir In The Garlic And Onion, And Cook Until The Onion Has Softened And Turned Translucent, About 5 Minutes. Pour In The White Wine, And Simmer For 2 Minutes. Stir In The Red Pepper Flakes, Butter, And Asparagus; Cook Until The Asparagus Is Just Tender, About 3 Minutes. Add The Shrimp And Lemon Juice, Continue Cooking Until The Shrimp Have Turned Pink And Are No Longer Translucent In The Center. Season To Taste With Salt And Pepper. Toss The Cooked Penne Pasta With The Shrimp And Asparagus Mixture. Sprinkle With Parsley And Parmesan Cheese To Garnish.