Broccoli Casserole - cooking recipe

Ingredients

1/2 medium onion
4 Tbsp. margarine
4 Tbsp. flour
2 1/2 c. milk
1/2 tsp. salt
1/4 tsp. pepper
1 egg yolk
1/2 c. Parmesan cheese
2/3 c. grated Cheddar cheese
2 pkg. frozen chopped broccoli

Preparation

Cut onion in small pieces.
Fry in margarine until soft.
Add flour, salt, milk and pepper to make a cream sauce.
Add egg yolk and cheese.
Add cooked and drained broccoli.
Put in casserole and sprinkle with bread crumbs.
Bake at 400\u00b0 for 30 minutes.