Bring A Large Pot Of Lightly Salted Water To A Boil. Add The Penne Pasta And 1 Tablespoon Of Olive Oil To The Pot, And Cook Until Pasta Is Almost Tender, About 6 Minutes. Drain. In A Large Skillet Over Medium Heat, Cook Bacon Until Browned. Stir In The Garlic And Cook For A Few Minutes, Then Add The Mushrooms. Cook, Stirring Constantly, For A Couple Of Minutes Until The Mushrooms Begin To Soften. Pour In The Chicken Stock, And Bring To A Boil. Allow To Simmer Over Medium Heat For About 3 Minutes. Add Cooked Pasta To The Pan, And Stir Until Coated. Simmer Uncovered Until The Sauce Has Reduced To Just A Few Teaspoons In The Bottom. Place Generous Servings Onto Plates, And Top With Parmesan Cheese.