01 - Combine ground turkey or chicken, egg, oats, red onion, Dijon mustard, garlic, parsley, smoked paprika, salt, and black pepper in a large bowl. Mix gently until just combined, being careful not to overwork the meat.
02 - Divide the mixture into 4 equal portions and shape each into a patty approximately 1/2 inch thick. Press lightly to compact without making them dense.
03 - Heat a nonstick skillet or grill over medium-high heat. Lightly oil the surface if necessary to prevent sticking.
04 - Cook the patties for 4-5 minutes per side until golden brown and fully cooked through, reaching an internal temperature of 165°F.
05 - Lightly toast the whole wheat buns on the grill or in a toaster for added texture and flavor, if desired.
06 - Build each burger by placing a lettuce leaf on the bottom bun, followed by a cooked patty, Greek yogurt, tomato slices, red onion, avocado if using, and finally the top bun.