Turkey Burger with Fennel and Apple Slaw

Ingredients

• 1 tablespoon olive oil
• 1/2 large onion, thinly sliced
• 3/4 cup mayonnaise
• 2 teaspoons apple cider vinegar
• 1 1/2 pounds ground turkey
• 1 1/4 teaspoons chili powder
• 1 teaspoon salt
• 3/4 teaspoon finely ground black pepper
• 1/2 teaspoon granulated garlic
• 1/2 teaspoon paprika
• 1/8 teaspoon cayenne
• 3/4 cup julienned Cosmic Crisp apple
• 3/4 cup thinly sliced fennel bulb (reserve fennel fronds for serving)
• 1 teaspoon olive oil
• 1 teaspoon freshly squeezed lemon juice
• Salt and freshly ground black pepper
• 4 slices cheddar cheese
• 4 burger buns, toasted
• 1 cup moderately packed baby kale