Remove the meat from the fridge 30 minutes prior to cooking to bring it up to room temperature.
Preheat the grill to medium-high.
In a large mixing bowl, combine the egg, parsley, flour, garlic, fennel (if using), salt, and pepper. Add the meat and use your hands to combine, being careful not to overwork it. Form 5 equal-size patties about 1 inch thick.
Grill the burgers, flipping once, until a thermometer inserted in the center registers 160℉/71℃ and the meat is no longer pink, 3 to 4 minutes per side. In the last minute, warm the pitas or rolls on the grill (if using).
We love these burgers topped with Garlicky Guac, Green Goddess Tahini Sauce, or Sweet Potato Hummus.
Notes
Flanagan, Shalane & Kopecky, Elyse (2018) Run Fast Cook Fast Eat Slow Rodale Publishing