2In large skillet, over medium heat, cook celery,red bell pepper and onion in margarine until tender.
Stir in flour and boullion. . Gradually stir in milk. Cook and stir until thickened and bubbly.
Remove from heat. Add cheese; stir until melted.
3Stir in the pasta and chicken.
4Spoon into a greased 9x13 baking dish.
Melt the 1/2 cup of butter and add to the crushed ritz crumbs, then add cheese and garlic powder, mix well and evenly coat the top of casserole
Cover. Bake 30 - 40 minutes remove the cover, and continue baking another 5 min or till golden brown...I used a deep dish pie plate for presentation..so it may not take as long to bake using a 9x13 pan.