In a skillet, cook bacon until crisp; drain. (If you are substituting already cooked crumbled bacon add to the cooked vegetables). Brown ground beef (use a small amount of bacon fat if necessary); drain. Toss onion, mushrooms, carrot and celery in flour; add to skillet with the broth. Worcestershire sauce, tarragon and pepper. Bring to a boil; reduce heat. Simmer, uncovered, for 15-20 minutes of until the vegetables are tender. Add bacon; transfer to a greased 2-qt. baking dish. Combine potatoes and 1/2 cup of cheese; spread over beef mixture. Sprinkle with paprika and remaining cheese. Bake, uncovered, at 350° for 20-25 minutes or until heated through. Broil 4 inc. from the heat for 5 minutes or until bubbly.