Step 1

Over medium heat melt the butter in a large pan until it starts to brown. Add in the onions and cook, occasionally stirring, until brown and softened.

Step 2

Next, turn up the heat to medium-high and add port wine and vinegar to the onions. Scrape the bottom of the pan to deglaze it and combine all the ingredients together.

Step 3

After that, add chicken broth, bacon, and the bouquet garni and bring to a boil. Reduce the heat, season with salt and pepper and let simmer for 45 minutes to an hour while skimming any foam that may form on top. Once done, remove the bouquet garni.

Step 4

Divide the soup into individual crock pots and place two croutons on top side by side. Cover with a generous amount of cheese while letting some cheese to hang over the edges of the crock.

Step 5

Place the crocks under a preheated broiler or in the oven at 220 °C until the cheese melts and bubbles and brown spots appear.

Step 6

One extra tip, when the cheese starts to flatten due to the heat in the oven, take the crocks out and using a propane torch melt and brown the cheese as desired.