Begin by slicing up the onions. Mince the garlic as well. Set aside.
Add the butter to a large pot. Let it melt completely and then add in all of the onions as well as a large pinch of salt and pepper.
Let the onions cook, on medium low heat for about 30 minutes or until they get caramelized. At the end, add in the garlic and cook for 1-2 more minutes or until garlic is fragrant.
Add in the red wine. Bring to a rolling boil and then reduce the heat to simmering for about 15-20 minutes or the wine has reduced tremendously.
Now that the wine has reduced, add in 2 heaping tbsp of all purpose flour and mix in. Let it cook for 2-3 minutes and then add in the beef broth.
Cover and let cook on medium heat for 15-20 minutes or so. Once done, taste and add salt and pepper to adjust seasoning.
If you are serving in a mini dutch oven/oven safe bowl….
Ladle the soup into the bowl. Add two 1.5 inch thick slices of the french baguette on top of the soup. Cover generously with the gruyere cheese. Place in the oven on broil for 1-2 minutes or until the cheese is melted. Garnish with fresh thyme.
If you don’t have an oven safe bowl….
Ladle the soup into a bowl of your choice. Slice the baguette into 1.5 inch slices and place on a sheet pan. Cover with the cheese generously and place on broil in the oven until the cheese is melted. Once done, simply place the cheesy bread directly on top of the soup bowl. Garnish with fresh thyme.