Step 1: In a large mixing bowl, combine the ground chicken, finely chopped spinach, shredded white cheddar cheese, breadcrumbs, chopped onion, minced garlic, Dijon mustard, Worcestershire sauce, salt, and black pepper.
Step 2: Use your clean hands to gently mix all ingredients until just combined. Be careful not to overmix, which can lead to tough burgers.
Step 3: Divide the mixture into four equal portions. Shape each portion into a round patty, approximately 1/2 inch thick. Press a small indentation in the center of each patty.
Step 4: Heat a drizzle of olive oil in a large skillet or on a grill pan over medium heat. Once hot, carefully place the patties in the skillet.
Step 5: Cook the burgers for about 5-6 minutes on the first side until golden brown and cooked halfway up the sides. Flip the patties.
Step 6: Cook for another 5-6 minutes on the second side, or until the internal temperature reaches 165°F (75°C) with a meat thermometer.
Step 7: While burgers cook, lightly toast your burger buns. Once burgers are done, place each patty on a bun.
Step 8: Add your favorite toppings such as lettuce, tomato, or extra cheese. Serve immediately with desired side dishes and enjoy!