Wash and cut of any stems of the green beans. Bring a pot of water to a boil, add a good amount of salt and blanch the green beans for 2-3 minutes. Drain and immediately cool in ice water or running cold water.

Chop up the mushrooms into small pieces

Prepare the sauce: Melt butter in a heavy pot or frying pan. Add the mushrooms and cook for 5 minutes until they are soft and juices are starting to come out.

Stir in the flour. Cook for 3 min. on medium heat.

GRADUALLY add in the milk and whisk constantly to keep clumps out.

Bring the milk to a boil slowly, make sure you stir constantly. Cook on very low heat at a bare simmer for 15-20 minutes or until thicker.

Make the fried onions: Heat 1 tbsp vegetable oil or butter in a frying pan. Fry onions on medium low until browned stirring often - it will take several minutes.

Toward the end when the onions have started to brown, sprinkle with a little flour to help crisp them up. Fry for another couple minutes until crisp.

Toss onions with 1/2 cup breadcrumbs

Preheat oven to 375°F/190°C. Arrange green beans in a baking dish big enough to hold them compactly. Pour over the sauce and spread out evenly.

Remove from oven. Sprinkle the onion breadcrumb topping on top and bake another 5-15 minutes until breadcrumbs are browned.

Serve and enjoy!