Preheat your oven to 350°F (175°C).
Prepare the green beans by trimming the ends and cutting them into 2-inch pieces.
In a large skillet, heat olive oil over medium heat and add the diced onions.
Add sliced mushrooms to the skillet and continue sautéing until they are soft.
Stir in the green beans, heavy cream, soy sauce, salt, and pepper.
Transfer the mixture to a baking dish and top it with French fried onions.
Bake in the preheated oven for 30–35 minutes, or until bubbling and golden brown.
Remove from the oven and let it cool slightly before serving.