1 cup diced celery
5 tablespoons butter
1 onion, chopped
½ green bell pepper, chopped
6 tablespoons all-purpose flour
1 (10.75 ounce) can cream of mushroom soup
1 (10.75 ounce) can milk
1 (6 ounce) can mushrooms
3 cups diced cooked turkey
1 (4 ounce) jar chopped pimento peppers
½ cup slivered almonds
salt to taste
1 cup soft bread crumbs
1 cup shredded Cheddar cheese
Preheat oven to 375 degrees F (190 degrees C).
Bring a large pot of lightly salted water to a boil; cook celery at a boil until tender, 5 to 10 minutes; drain.
Heat butter in a skillet over medium heat; cook and stir onion and bell pepper in the melted butter until softened, 5 to 10 minutes. Whisk flour into onion mixture until the butter and flour form a paste. Add mushroom soup, milk, and mushrooms; cook, stirring occasionally, until mixture is smooth, 5 to 10 minutes.
Mix turkey, celery, pimento peppers, almonds, and salt into mushroom soup mixture; cook and stir until heated through, about 5 minutes. Pour mixture into a 2-quart casserole dish; top with bread crumbs and Cheddar cheese.
Bake in the preheated oven until casserole is bubbling and cheese is melted, 30 to 40 minutes.