• Prep: Slice the onions thinly, the thinner the better so they cook a bit faster.
• In a large pan on medium heat, add the butter and melt it. Add the sliced onions and let them cook for 1 minute or so before you stir them. Then add a little bit of salt to the onions and mix well, turn to low heat and keep stirring every 5 minutes or so. 
• When the onions start browning, add a splash of cognac to deglaze and keep cooking until all the onions are translucent and soft golden brown. 
• Add in the flour and cook it for 1-2 minutes or so, stirring constantly to avoid it from burning. Add a splash of the beef stock and dilute the flour in it and mix well to combine.
• Once the flour has mixed well and completely dissolved, transfer the caramelized onions from the pan to the slow cooker. Continue to add the rest of the beef stock and herbs to the slow cooker and mix well. 
• Cook: Set the crockpot on low heat and cook for 5-6 hours. Towards the last 30 minutes, carefully taste the soup and add the salt and pepper as desired.
• Assemble bowls: Preheat the oven to 400º F. Slice the baguette bread, place it on a baking sheet and toast bread for 5-7 minutes.
• In oven safe soup bowls pour the onion and broth mixture into each bowl, top each bowl with 2 slices of bread and add grated cheese on top.
• Change oven setting to broil, place the full soup bowls in the oven and broil for 8-10 minutes. Be very careful when removing them from the oven! Serve and enjoy!

Instructions for Stovetop method

• Prep: Follow the same instructions as in the Slow Cooker Method, except use a Dutch oven or large pot.
• Cook: Set the heat to low and let the mixture cook for 5-6 hours. Towards the last 30 minutes, carefully taste the soup and add the salt and pepper as desired.
• Assemble bowls: Complete the same steps as in the slow cooker method to assemble and complete each soup bowl. Enjoy!