Add the ground chicken, red peppers, and diced onion to a large bowl.
Mix in the crumbled feta, spinach, panko crumbs, and minced garlic.
Add oregano, salt, pepper, and lemon juice. Mix gently until combined.
Form mixture into four even patties, not too tightly packed.
Heat skillet on medium heat and lightly oil it.
Cook patties for 6–7 minutes per side until golden brown and internal temp reaches 165°F.
Let rest before serving on buns with desired toppings.
Notes
Use a meat thermometer to ensure patties reach 165°F. Burgers may be frozen before or after cooking. Try serving with tzatziki or red onions for added flavor!