Add the onions and cook until tender, about 5-7 minutes.
Add the mushrooms and saute until the mushrooms start to caramelize, about 10-15 minutes.
Add the garlic and thyme and saute until fragrant, about a minute.
Sprinkle then mix the flour in and cook for another 2 minutes.
Add the white wine and deglaze the pan.
Add the broth and cream and simmer until it thickened, about 2-3 minutes.
Add the cheese and let it melt, season with salt and pepper and remove from heat.Bring a large pot of water to boil, add the green beans, cook until they just start to turn tender and plunge then them into cold water.
Serve the green beans topped with mushroom sauce and french fried onions.