Preheat oven to 350° F.

In a sauce pan. Add green beans and cover with water.

Place sauce pan with green beans on the stove and turn on high.

Once boiling, reduce heat to low-medium and cook until fork tender. About 15 minutes.

Drain cooked green beans and place in a greased 13" x 9" baking dish, set aside.

Slice the mushrooms and small onion.

In a large skillet, melt butter on medium heat. Then add sliced mushrooms and half of your sliced onions to the pan. Cook until mushrooms are soft and onions are translucent about 5 minutes.

Next, in a measuring cup combine the milk, cornstarch, low-sodium soy sauce, salt, and pepper together using a whisk to prevent lumps.

Once combined, pour mixture into skillet with the cooked mushrooms and onions.

Stir well and regularly until the mixture begins to thicken like a soup. About 5-10 minutes on low-medium heat.

Once thickened, turn off the heat. Pour mixture onto the green beans in the baking dish. Carefully stir to coat.

Bake in preheated 350° F oven for 20 minutes.

Remove casserole from oven and sprinkle the top with homemade french fried onions.

Allow to cool for 5 minutes before serving.

Fill the bottom of a skillet with ½ inch of oil (vegetable, canola, or peanut) for frying your onions.

In a bowl toss the reserved half of the sliced onions with flour until coated.

Heat on medium-high. Once the oil is hot, add the floured, sliced onions. Cook until brown in color.

Remove fried onions from skillet and allow to drain on paper towels. Set aside until ready to top your green bean casserole.