Heat an instant pot on sauté, Cook the bacon until crisp and drain on a paper towel. Add one tablespoon of olive oil to the pot. Brown the beef in batches and set aside. Melt the butter in the pot and add the onions. Scrape any brown bits from the bottom of the pot. Cook until soft and add the sugar and thyme. Cook the onions until caramelized. Add the remaining flour to the pot and cook for one minute. Add the beer, stock, mustard, vinegar, and bay leaves. Add the beef to the pot. Place the lid on the pot and turn it to meat/stew normal. Cook for 30 minutes. Allow the pressure to release on it's own. Serve with roasted potatoes and vegetables.