Start by setting the saute setting on your pressure cooker. Wait about 30 seconds, and then add your butter. Let the butter melt for about 30 seconds, then add your sliced onions, brown sugar, and salt, and mix well. Allow the onions to saute for 8-10 minutes.
It's important that you use a wooden spatula to remove any onions at the bottom. Otherwise, you will get a BURN notice. Add the beef broth, Worshire Suce, bay leaf, and black pepper, mi well. Then add the pressure cooker lid and then move the valve into the sealed position. Set manual high pressure for 5 minutes.
Allow the pressure to come down naturally. Then open your lid, and mix well.
Add a couple of slices of baguette into your oven-safe bowl, ladle the soup into the bowl, and add a couple of cheese slices. Place in the broiler for 2-4 minutes or air fry at 300 degrees F, for 3-5 minutes or until the cheese is melted.