Ingredients .33 cup(s) mayonnaise2 tablespoon(s) whole grain mustard1 tablespoon(s) apple cider vinegar1 tablespoon(s) sugar1.5 teaspoon(s) kosher salt divided1.25 pound(s) ground turkey preferably a mix of dark and white meat, shaped into 4 (4 1/2 to 5-inch) patties1/2 finely ground black pepperCanola oil for greasing.25 pound(s) Gruy??re cheese sliced4 hamburger rolls such as challah buns, split2 cup(s) thinly sliced red or green cabbage or a mix of both
Note: For a twist on traditional coleslaw, shred Brussels sprouts on a box grater and use in place of the cabbage.
Preheat a grill to medium-high heat. Meanwhile, in a large bowl, whisk together mayonnaise, mustard, vinegar, sugar and 1/2 tsp. salt; set dressing aside.
Season turkey patties all over with remaining 1 tsp. each salt and pepper. Carefully grease grill grates with oil, arrange patties on grill, and cook, flipping once, until deep golden brown and cooked through, about 10 minutes. During the last few minutes of cooking, top burgers with cheese and toast buns on grill until golden brown, 1 to 2 minutes.
Add cabbage to reserved dressing and toss well. Arrange burgers on buns, top with slaw, and serve.