Ingredients 4 large onions, thinly sliced 3 tbsp unsalted butter 1 tbsp olive oil 2 garlic cloves, minced 1 tbsp all-purpose flour 1/2 cup dry white wine 4 cups beef stock (or chicken stock for a lighter flavor) 1 bay leaf 1 tsp fresh thyme leaves Salt and pepper, to taste 4 slices ba