There are so many ways to make a hamburger and I don't think we Americans ever get tired of the "research." I love a plain burger, but I also love adding extra flavor to the meat mixture. Some people like to mix butter into their burgers, but I go back to one of my big childhood favorites: Worcestershire. You can use ground turkey breast or thigh meat here. The thigh meat is juicier by nature but less lean. Cooking them in stock yields a tender burger either way. What about cheese? I lived in France and enjoyed the finest goat cheeses from the Loire Valley and the tastiest cow's milk tomme from the French Alps. I also happen to love melted American cheese at the right time and place, and this burger is that place. I always serve cornichon pickles (or bread-and-butter slices) along with the onion jam.