Heat the oven to 400°F. Slice the top off the 1 head garlic head to expose the cloves, drizzle with 1 tbsp olive oil, and wrap in foil. Roast for 35–45 minutes, until the cloves are deeply golden and soft.
1 head garlic, 1 tbsp olive oil
While the garlic roasts, place the 1 poblano pepper over a gas flame or under the broiler, turning occasionally, until the skin is blackened and blistered all over. Place it in a bowl and cover with plastic wrap. Let sit for 5–10 minutes to steam the skin off. Peel away the charred skin, remove the stem and seeds, and finely chop the pepper.
1 poblano pepper
Scoop the 2 ripe avocados into a bowl and mash until mostly smooth, leaving a few chunky pieces. Squeeze in the 1 tbsp fresh lime juice, then add the chopped poblano, roasted garlic, 2 tbsp red onion, 2 tbsp fresh cilantro, ½ tsp salt, and ¼ tsp black pepper. Mash gently until everything is combined.
2 ripe avocados, 1 tbsp fresh lime juice, 2 tbsp red onion, 2 tbsp fresh cilantro, ½ tsp salt, ¼ tsp black pepper
Divide the 1½ lbs ground turkey into eight loose portions. Get the cast iron skillet hot and lightly coat with 1 tbsp neutral oil.
1½ lbs ground turkey, 1 tbsp neutral oil
Working in batches, place the turkey portions onto the cast iron. Immediately press each one firmly with a sturdy spatula until very thin, about ¼ inch thick. Season each burger with even amounts of the 1½ tsp salt, 1 tsp garlic powder, ½ tsp smoked paprika, and ½ tsp black pepper.
1½ tsp salt, 1 tsp garlic powder, ½ tsp smoked paprika, ½ tsp black pepper
Cook on the first side for about 2–3 minutes, until the edges are browned and crisp. Flip, add a slice of the 4 slices pepper jack cheese to each of the burgers, and cook for another 1–2 minutes, until the turkey is cooked through and the cheese is melted.
4 slices pepper jack cheese
Spread a generous layer of guacamole over the bottom bun of each of the 4 brioche burger buns. Stack two turkey patties on top, then finish with Thinly sliced red onion and Thinly sliced jalapeño. Add the top bun and serve immediately.
4 brioche burger buns, Thinly sliced red onion, Thinly sliced jalapeño