Melt butter in a large pot over medium low heat. Once melted, add sliced onions and toss to coat in butter. Top with a lid and allow to soften for about 10 minutes.
Once soft, add minced garlic, thyme, and bay leaves. Recover.
While the herbs soften, approximately 20 minutes, cut slices of Brownberry Oatnut bread the size you desire. Brush with olive oil and toast to perfection. Remove after toasting and set aside.
Once herbs have softened, remove lid and turn up the heat to medium. Cook until the onions have browned and most the liquid has evaporated, this could take up to an hour. Continue to stir throughout the hour so the onions don’t stick or burn. Once done, remove the bay leaves and thyme stems.
Once herb remnants are removed, add sherry, wine and a little salt and pepper. Allow to absorb for about 3 minutes, until the onions are dry again.
Add the flour and stir until it cooks out. When the flour has cooked out add the beef broth and let it simmer for 10 minutes, until it has reduced a bit and comes back to a boil.
Ladle soup into your bowl, leaving some room at the top.
Add your toasted Brownberry Oatnut bread pieces and top with your parmesan and gruyere cheese.
Broil on low for about 5 minutes or until cheese is melted.