Over medium heat, add olive oil to a dutch oven.
Once the oil is hot, add the onions to the dutch oven and stir.
Cook the onions for 10-12 minutes or just until the edges begin to brown.
Stir in brown sugar, butter, and garlic.
Continue cooking until onions are browned and there is a glaze on the bottom of the pan.
Pour in white wine and deglaze the dutch oven.
Turn stove heat down to low.
Add beef broth, bay leaves, salt, and pepper, and cover with a lid.
Cook for 30 minutes.
Remove the lid and let the soup simmer for another 10 minutes.
Chop the baguette into small pieces as desired.
To build the soup, place baguette pieces at the bottom of the bowl, spoon soup into the bowl, top with more pieces of baguette, and then sprinkle cheese on top.
Broil on HIGH for 3-5 minutes, remove from the oven, and serve!