Herbed Chicken and Apple Burgers

Ingredients

• 1 lb ground chicken
• 1 large red onion (finely chopped)
• 1/4 cup plain dry bread crumbs
• 2 large green apples (such as Granny Smith (for a tart taste) or Golden Delicious (for a sweet taste), peeled and coarsely grated)
• 1 tbsp fresh sage leaves (chopped)
• 1 tbsp fresh thyme leaves
• 1/4 tsp salt
• 1/4 tsp Freshly ground black pepper
• 1/4 cup Dijon mustard
• 1 tbsp honey
• 4 whole-wheat hamburger buns (split)
• 6 tbsp watercress sprigs (large stalks discarded)