Combine the ground chicken, crumbled feta cheese, finely chopped onion, minced garlic, freshly chopped herbs, dried oregano, lemon zest, lemon juice, breadcrumbs or almond flour, and beaten egg in a large bowl. Season with salt, pepper, and optional red pepper flakes. Mix gently with your hands until just combined, being careful not to overmix.

Shape the mixture into patties, approximately 4-6 ounces each. Create a slight indentation in the center of each patty to help them hold together. Cover and refrigerate for about 30 minutes.

Preheat your grill, pan, or oven to medium heat (around 375°F for baking). Make sure grill grates are clean and lightly oiled, or use a non-stick skillet with olive oil for pan-searing.

Cook the patties on the grill or in the heated pan for about 6-7 minutes on each side, or until they reach an internal temperature of 165°F. If baking, place on a lined baking sheet and cook for 20-25 minutes, turning halfway.

Once cooked, let the burgers rest for a few minutes to allow juices to redistribute.

Serve warm with fresh veggies, tzatziki sauce, and either pita or whole grain buns.