SHELL CASSEROLE

1 lb. lean ground beef
1 small onion, chopped
1/2 tsp. salt
1/4 tsp. garlic powder
1 tsp. Worcestershire sauce
1/4 cup all purpose flour
1 1/4 cups hot water
2 tsp. beef bouillon granules
6 oz. large shell shaped pasta
1 (2 oz.) can sliced mushrooms, drained (optional)
1 cup sour cream

In a skillet, cook ground beef and onion until red color disappears.  Drain beef; place in slow cooker.  Stir in salt, garlic powder, Worcestershire sauce and flour.  Add water and bouillon.  Mix well.  Cover and cook on LOW 2 to 3 hours.  Meanwhile, cook pasta according to package directions and drain.  Add cooked pasta, mushrooms and sour cream to slow cooker; stir to mix ingredients.  Turn control to HIGH.  Cover and cook on HIGH 10 to 15 minutes.