Chicken Dumpling Casserole

1/2 cup chopped onion
1/2 cup chopped celery
2 minced garlic cloves
1/4 cup butter
1/2 cup AP flour
2 tsp sugar
1 tsp salt
1 tsp dried basil
1/2 tsp pepper
4 cups chicken broth
10 oz frozen peas
4 cups cooked cubed chicken
2 cups buttermilk biscuit mix
2 tsp dried basil
2/3 cup milk

In a large saute pan, saute onion, celery and garlic in butter until tender. Add flour, sugar, basil, pepper, and broth. Bring to a boil. Cook and stir for 1 minute. Reduce heat. Add peas and cook for 5 minutes, stirring constantly. Stir in chicken. Pour into greased 13 x 9 inch baking dish. For dumplings, combine biscuit mix and basil into a bowl. Stir in milk with a fork until moistened. Drop by Tbsp-ful onto casserole. Bake uncovered at 350 for 30 minutes. Cover and bake 10 minutes more, or until dumplings are done.