In large mixing bowl, add ground turkey, spinach, feta, garlic, cumin, salt and pepper. Using your hands or spatula, mix well.
Using wet hands, form 4 large turkey burger patties, place on a platter and make an indent in the center. If grilling on outdoor grill, freeze patties for 10 minutes to prevent from falling apart.
To pan fry burgers: Preheat large non-stick skillet or a grill pan on low-medium heat and swirl oil to coat. Add turkey burger patties, cook for 5 minutes or until golden brown, flip and cook for another 4-5 minutes or until thermometer inserted in the center registers 165F.
To grill turkey burgers: Preheat grill on medium-high heat and oil grill grates well. Spray turkey patties on both sides with cooking spray, place on a grill and cook for 8-10 minutes flipping once. Grills vary, so check your burger with a meat thermometer.
It's best to serve spinach feta turkey burgers hot and immediately for maximum juiciness. Serve traditional way on a bun or in a lettuce wrap with all the fixins.
Notes
Store: Refrigerate in an airtight container for up to 5 days or freeze leftovers for up to 3 months.
Freeze: Lay patties on a baking sheet lined with parchment paper, freeze completely and then transfer to a large Ziploc bag. Cook from frozen following recipe's instructions + 5 minutes.
Forming patties: Shape patties a bit wider than the bun since they shrink during cooking.
Indoor grilling: Don't use a panini press grill as it presses all the juices out of burgers. Indoor one sided grill or grill skillet is fine.