Mix together ground turkey, grated parmesan cheese, egg white, salt & pepper and 1 tbsp taco seasoning.
Heat the grill- and meanwhile, form the mixture into patties. Grill for about 4-5 minutes per side or until internal temperature reads 165 F.
Meanwhile, add sliced onions and bell peppers to a skillet over medium high heat. Sprinkle another tbsp of taco seasoning to the mixture. Cook for about 5 minutes.
Once burgers are cooked- remove from grill and top with bell peppers and onions. Serve with salsa or other toppings as desired.