This is a keeper! I saved some of the shallot from the mushrooms and added that to the burger with a little worcestershire for moisture. I also added some fresh thyme and sage to the mushroom mixture and deglazed with a little sherry. A little whole grain dijon to the dressing for the arugula balanced out nicely. Open-Face Turkey Burgers with Gruyere, Mushrooms, and Arugula Salad Recipe | Bon Appétit (bonappetit.com)