In a large pot, over medium-high heat, bring two quarts water and 1 teaspoon salt to a full rolling boil. Gradually add macaroni and boil approximately 15 minutes or until pasta reaches desired tenderness. Drain.
Melt butter and olive oil in a saucepan over medium heat. Sauté shallots in butter and olive oil for approximately 2 minutes or until they begin to turn transparent. Add flour to the pan, stirring constantly until a smooth paste forms. Stirring constantly, gradually add milk and continue cooking until mixture is thick and bubbly (mixture should coat the back of a spoon). Add 6 ounces of the cheese and stir until completely melted. Remove from heat and add beer, bacon, mustard, garlic powder, pepper and remaining salt. Stir well.
Spray a 9” x 9" square glass pan with non-stick cooking spray. In the large pot, combine macaroni and cheese sauce and stir. Pour into 9” x 9" baking dish, cover with foil and place into preheated oven and bake for 15 minutes. After 15 minutes, remove foil and sprinkle the remaining 2 ounces of the shredded cheese and continue cooking, uncovered for another 15 minutes.
Remove macaroni and cheese from the oven. Allow to cool for approximately 5 minutes before serving.