Peel your onions, then slice off the ends of each onion and continue slicing so onions are in circles about 1/3 inch wide.
Cut the onion circles in half. I like to leave mine in larger pieces and have longer, thinner onions in my soup.
Set your instant pot to sauté.
Place the butter into the bottom of the Instant Pot. Add the sliced onions and the brown sugar.
Cook the onions, stirring every 2-3 minutes, until they have browned and caramelized. The brown sugar will help with this step! This can take a solid 45-60 minutes. Make sure to scrape all of the browned bits off the bottom of the Instant Pot when they appear and stir them back into the onion mixture.
If anything starts to burn, add a tablespoon of water quickly and keep cooking. Make sure to scrape all of the browned bits off the bottom of the Instant Pot when they appear and stir them back into the onion mixture.
When the onions are done, slowly pour 1/2 cup of the beef broth into the bottom of the pot. Deglaze the bottom by scraping the browned bits off the bottom using a wooden spoon.
Add in the remaining beef broth. the cooking sherry to taste, the Worcestershire to taste, pepper, and thyme. Depending on how thick you like your soup, you can add more beef stock to the pot. I like mine restaurant-style, so there's lots of onions and just enough broth to make it a soup.
Taste test and add beef bouillon granules if desired. French onion soup should have an extraordinarily strong beef stock, and you can adjust this to your liking at this point. If desired, add salt at this point, but you rarely need it if you have a proper beef stock.
Add the bay leaf.
Place the Instant Pot lid on the pot and turn the valve to sealing.
Press the soup button and set the time for 10 minutes.
Once the time is up, let the Instant pot naturally release.
At this point skim any foam off the top of the soup, do NOT mix it in! Then remove the bay leaf.
Spoon the soup into ramekins or your favorite oven safe soup bowls leaving at least one inch to the top edge.
Place 1-2 slices of the toasted baguette onto the soup.
Top the baguette with the shredded Gruyere.
Place the ramekins on a baking sheet and broil in the oven, with the oven rack set in the middle position, for about 3 minutes. Watch for the cheese to start to melt then brown, then remove from the oven.
Let the soup and the soup bowls cool for 5-10 minutes before serving.
All calories and info are based on a third party calculator and are an estimate. Actual nutritional info will vary with brands used, your measuring methods etc.