1. Add the onion to the bowl fitted with the ultrablade. Mix at speed 11 for 20 seconds.
2. Replace the ultrablade with the mixer blade. Add oil, butter and salt and set the P2 Simmer program so that the onions can brown all the way through.
3. At the end of the program, add sugar and cook at speed 2 at 200°F for 5 minutes to caramelize the onions.
4. Add the flour, stock and water and set the P3 Simmer program without the stopper.
5. Spoon into bowls and season with pepper.