01 - In a bowl, combine ground turkey, chopped onion, minced garlic, parsley, smoked paprika, cumin, salt, and black pepper. Mix gently until just blended.
02 - Divide the mixture into four equal portions and form into patties.
03 - Heat olive oil in a skillet or grill pan over medium heat. Cook patties 5 to 6 minutes per side, until golden brown and internal temperature reaches 165°F (74°C). Remove and let rest.
04 - In a bowl, mash avocados until mostly smooth. Stir in diced tomato, red onion, jalapeño if used, chopped cilantro, lime juice, salt, and black pepper. Adjust seasoning as desired.
05 - Lightly toast burger buns, if preferred.
06 - On bottom bun, layer lettuce, turkey patty, a generous spoonful of guacamole, sliced tomato, and sliced red onion. Top with bun halves.
07 - Serve immediately while warm.