Directions

1. Set pressure cooker to "sear", adjust time to 15 minutes, press "start/stop", and add 4T butter. When melted, add onions and baking soda. Cook onions until caramelized and dark brown, about 10-15 minutes.
2. When onions are done and brown, add sherry and deglaze pot until alcohol is cooked off, about 3-4 minutes.
3. Add chicken stock, apple cider vinegar, fish sauce, thyme sprigs, and bay leaf. Continue simmering.
4. While cooking, spread butter on bread slices. Sprinkle garlic on one side of each. Place bread in oven rack and toast bread.
5. When soup is done, remove bay leaf. Ladle soup into serving bowls. Place one slice toasted bread in soup.

6. Sprinkle Gruyére on top of bread. Place bowls of soup in a very hot oven to melt and brown cheese. Serve.