Bring A Large Pot Of Lightly Salted Water To A Boil Over High Heat. Add The Farfalle Pasta, And Cook Until Al Dente, 8 To 10 Minutes; Drain. Meanwhile, Heat The Olive Oil In A Large Skillet Over Medium-High Heat. Stir In The Italian Sausage Until Crumbly And No Longer Pink, About 5 Minutes. Stir In The Garlic, And Continue Cooking Until The Sausage Begins To Brown, About 5 Minutes More. Pour Off The Excess Grease, Then Pour In The Chicken Broth And Red Pepper Flakes. Bring To A Boil Over High Heat, Then Add The Broccoli Rabe, And Cover. Cook Until The Broccoli Rabe Is Tender, About 4 Minutes. When The Broccoli Rabe Is Done, Stir In The Butter, Parmesan Cheese, Salt, And Pepper Until The Meat Sauce Has Thickened. Toss With The Farfalle And Serve.