Preheat your oven to 375°F if baking.
In a large bowl, combine the ground turkey, well-dried kale, red onion, sun-dried tomatoes, feta, garlic, oregano, salt, and egg.
Mix gently with clean hands or a sturdy spoon. Avoid over-mixing, which can make the burgers tough.
If the mixture feels too wet to form into patties, add a small amount of gluten-free breadcrumbs.
Shape into 9 even patties and place on a parchment-lined baking sheet.
Bake at 375°F for 30–35 minutes, flipping once after 25 minutes. Check that the internal temperature reaches 170°F. Do not over cook either, as this will also cause the burgers to get dry and crumbly.
Alternatively, grill on medium heat, flipping once, until the burgers are fully cooked through and reach a temp of 165F.