Preheat the oven to 350F.
Add green beans, ½ cup of filtered water, and a few dashes of salt to a skillet and cover. Saute over medium-high heat for 15-20 minutes or until green beans have softened and water has evaporated. Transfer to a baking dish.
Add mushrooms and olive oil to a skillet and cover. Saute over medium heat for about 10 minutes. Set aside.
Blend cashews, vegetable stock, and garlic in a high-speed blender until completely smooth to make sauce. Pulse in cooked mushrooms.
Stir sauce into green beans and salt and pepper to taste.
Bake uncovered for 25 minutes or until it’s hot and bubbling.
Top with fried onions and broil for about 2 minutes, until onions are lightly browned.