In a large mixing bowl, combine the ground turkey, Cajun seasoning, chopped red onion, minced garlic, and chopped jalapeño.
Add the breadcrumbs and the egg to the meat mixture. Season with salt and pepper, and mix until everything is well combined but don't overwork the meat.
Divide the mixture into 4 equal portions and shape each portion into a patty.
Preheat a grill or a skillet over medium-high heat and lightly grease with cooking spray or oil.
Cook the turkey patties for about 5-6 minutes on each side or until they are cooked through and reach an internal temperature of 165°F (74°C).
In the last minute of cooking, place the burger buns on the grill/skillet to toast them lightly.
Once cooked, remove the patties from heat and let them rest for a minute. Assemble the burgers by placing a turkey patty on a bun, topped with lettuce, sliced tomatoes, and avocado.
Add a few drops of hot sauce on top for an extra kick if desired.
Place the top bun on and serve immediately.
Notes
Serve with a side of sweet potato fries and extra hot sauce for dipping.