Mix together the ranch dressing, minced pickled jalapeños, and lime juice in a small bowl to create the jalapeño ranch—this can be done while you prepare everything else. While that sits, pound the chicken breasts to an even 1/2-inch thickness (this ensures even cooking and prevents dry edges). Slice the red onion into 1/8-inch rings, slice the tomatoes, and arrange the lettuce on a plate for easy assembly later. Having everything prepped before you start cooking will make the assembly seamless.

Preheat your grill to medium heat (around 375-400°F if using a temperature gauge). While the grill heats, pat the chicken breasts dry with paper towels, then coat them with avocado oil and season both sides generously with kosher salt, cracked black pepper, and garlic powder. I like to let seasoned chicken sit for a few minutes before grilling—it helps the flavors penetrate the meat rather than just sitting on the surface.

Place the seasoned chicken on the hot grill and cook for 3 to 5 minutes without moving it—this creates a nice char and helps the meat release naturally from the grates. Flip the chicken and cook for another 3 to 5 minutes on the second side. During the last minute of cooking on the second side, place a cheddar slice on top of each breast and close the grill lid to let the cheese melt completely.

While the cheese is melting, butter the inside of each brioche bun and place them cut-side down on the grill grates for 1 to 2 minutes until they're lightly toasted and golden. Remove the chicken and buns from the grill. Spread the jalapeño ranch dressing from Step 1 on the bottom half of each toasted bun, then layer with green leaf lettuce, tomato slices, red onion rings, cheese-topped chicken, and extra pickled jalapeño slices. I always put the lettuce down first—it creates a barrier that keeps the bun from getting soggy from the tomato and jalapeños.

Place the top bun on each sandwich and serve immediately while everything is still warm. The brioche buns should still be warm and slightly crispy, the chicken juicy, and the cheese perfectly melted.