Duck Burgers With Pickled Fennel and Prune Mayonnaise Recipe

Ingredients (10)

• 2 1/2-pound duck breasts
• 2 teaspoons whole grain mustard
• 1 tablespoon sliced chives, plus extra for stacking on the burger
• Kosher salt and freshly ground black pepper
• 3 soft pitted prunes, plus a few extra for garnish
• 1/4 cup mayonnaise
• 2 brioche or other buns, halved horizontally and lightly toasted
• 4 leaves gem or green leaf lettuce
• 1 recipes Quick Pickled Fennel, or other pickles as desired
• Cornichons, to serve alongside