Preheat oven to 350 degrees. Grease a small baking dish or casserole dish.
Melt the butter over low heat. Add onions and cook until softened. Add flour and stir until smooth and bubbly.
Add the spinach liquid and evaporated milk and cook until thick stirring constantly. Add pepper, salt, celery powder, garlic powder, Worcestershire sauce, crushed red pepper, and cheese. Stir until melted.
Add spinach and blend very well. Pour into a greased baking dish or casserole and top with breadcrumbs. Bake for 30 minutes. May be frozen.