In a large mixing bowl, combine ground chicken, egg, breadcrumbs, diced red bell pepper, green onion, smoked paprika, Cajun seasoning, sea salt, black pepper, and garlic.

Mix the ingredients gently until just combined, being careful not to overwork the mixture.

Divide the mixture into four portions and roll each into a ball.

Heat avocado oil in a large skillet over medium heat until shimmering.

Place the chicken balls in the skillet, cover with parchment paper, and press down firmly with a spatula to smash them into flat patties.

Cook the patties undisturbed for 4-5 minutes until golden brown on the bottom.

Flip the patties carefully and place a slice of cheddar cheese on each patty.

Cover the skillet with a lid and cook for another 3-4 minutes until the cheese melts and the chicken is cooked through.

Toast the brioche buns until golden.

Mix sriracha into mayonnaise to your desired spice level and spread it on both halves of each bun.

Assemble the burger by placing two cheesy smash chicken patties on the bottom bun, topping with red onion slices and bacon, and then placing the top bun on.