Peel and slice the onions. Peel and crush the garlic.
Melt the butter with 1 tablespoon of olive oil in a large saucepan. Brown the onions and garlic over very low heat.
Add 500 ml of water, the broth, the wine and the bay leaf. Season with salt and pepper. Bring to a boil. Lower the heat, cover and simmer for 20 minutes stirring occasionally.
Toss the green beans in a large volume of salted boiling water. Cook for 15 minutes before serving.
To serve, remove the bay leaf, pour the soup in 2 bowls, sprinkle with grated gruyère and grill for 5 minutes. The gruyère should be nicely golden.
Grill the slice of bread in the oven. Drizzle with a little olive oil and sprinkle with pepper.
Drain the beans. Add a little olive oil and sprinkle with salt crystals and pepper.
Pour the onion soup in two plates, over the grilled whole-wheat bread, and serve with green beans.