Poor Man's Lobster Thermidor

I got this recipe out of the Mennonite cook book More With Less. I have had tilapia in my freezer for the longest time and was looking for new recipes to use it in. I added celery to this recipe, as well as extra random spices. I topped it with buttered breadcrumbs mixed with spices and grated Parmesan cheese. It was really good1

Ingredients:

2 tbsp. chopped onions
1/2 c. mushrooms
2 tbsp. butter
2 tbsp. flour
1/2 tsp. salt
Dash of pepper
Dash of paprika
1/2 c. milk
1/2 c. chicken broth
1/2 tsp. Worcestershire sauce
1 egg yolk
2 tbsp. cooking wine (optional)
2 c. cooked white fish pieces
Buttered bread crumbs
Grated cheese

Preheat oven to 425 degrees. Saute first 3 ingredients. Add next 4. Cook until bubbly, add next 3. Cook, stir until thickened, add egg yolk and wine and fish. Place in shallow baking dish, top with cheese and bread crumbs. Bake about 8 to 10 minutes until brown.