Cook noodles according to package directions until al dente. Strain. In large pot melt butter on medium heat and stir in flour until lightly golden brown. Stir in heavy cream.
Stir in shredded cheese and garlic powder until smooth and melted. Add salt and pepper to taste. Fold in your cooked noodles, stir to coat. Fold in your diced leftover brisket until coated and warmed. Enjoy.