1. Slice onions thinly.
2. Add butter and olive oil to a 6-8 qt pot. Heat until it begins to boil.
3. Add the onions and disperse the salt. Heat over medium heat, stirring occasionally, for 45 minutes.
4. Deglaze with bourbon and white wine. Bring up to a boil and reduce to about 70 percent of total volume.
5. Add beef stock and a bundle of thyme. Season to taste with salt and simmer for 20-30 minutes.
6. Finish with sherry, simmer for 1-2 minutes, remove from heat and add butter until melted and emulsified. Season to taste with salt and pepper.
7. Grate gruyere and gouda cheese. Toss together.

With oven-safe bowl:

1. Brush ½ in slices of baguette bread with olive oil at 425℉ or 218℃, until crisp but not brown for 5-7 minutes.
2. Ladle soup into oven-safe bowls
3. Leave a quarter inch of space, place under high broiler 2-3 min.
4. Serve

Without oven-safe bowl:

1. Melt cheese and bread in the oven – serve on the side (2nd option)