I absolutely LOVE this soup! We had a snow day today and this was the perfect thing to make. I added one spoonful of the flour mixture to the broth and it immediately clumped and so like others recommended, I added some broth to the mixture before adding the rest. I still whisked it a lot though, as I prefer the onion in smaller pieces so didn't mind them falling apart. I also cut down the original simmer time to about 40 minutes, adding the salt and pepper after about 10. This may be my favorite soup ever and will be making this often! Also - I used 6 extra large bouillon cubes - instead of 8 large, which I think is about the same amount or slightly less.