Step 1

Stir ½ cup mayonnaise and 2 Tbsp. adobo sauce from a can of chipotle chiles in adobo in a small bowl to combine. Chill chipotle mayo until ready to serve.

Step 2

Heat 1 Tbsp. vegetable oil in a large cast-iron skillet over medium. Add 1 medium red onion, finely chopped, and sprinkle with ½ tsp. Diamond Crystal or ¼ tsp. Morton kosher salt. Cook, stirring often, until onion is beginning to soften, about 4 minutes. Add 3 garlic cloves, finely chopped, and cook, stirring often, until softened, about 2 minutes. Add 1 tsp. ground cumin and ½ tsp. ground coriander and cook, stirring, until spices are fragrant, about 30 seconds. Remove from heat and let cool 5–10 minutes.

Step 3

Meanwhile, cut 6 oz. pepper Jack cheese (from one 8-oz. block) into 8 slices; set aside. Coarsely grate remaining 2 oz. pepper Jack cheese.

Step 4

Coarsely mash one 15-oz. can black beans, rinsed, in a large bowl with a fork. Add grated cheese, 1 large egg, beaten to blend, 2 chipotle chiles in adobo, chopped, ½ cup plain dried breadcrumbs, and 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt. Scrape in onion mixture; reserve skillet. Mix until ingredients are evenly distributed.

Step 5

Divide bean mixture into 8 portions (about ¼ cup each) and roll into tight balls between your palms. Working in 2 batches and using fresh parchment paper for each batch, sandwich balls between 2 sheets of parchment paper, spacing 6" apart, and firmly smash with a meat mallet or heavy skillet to create thin 4"-diameter patties.

Step 6

Spread 4 brioche buns, split, with unsalted butter, room temperature. Wipe out reserved skillet and place over medium heat. Working in batches, toast buns, cut side down, in skillet until golden brown and warmed through, about 2 minutes. Transfer to a baking sheet and let cool slightly.

Step 7

Add 1 Tbsp. vegetable oil to skillet and heat over medium-high. Working in batches of 3 or 4 and adding more oil if skillet looks dry, cook patties, undisturbed, until deeply browned underneath, about 3 minutes. Flip and cook until edges are beginning to brown, about 2 minutes. Place a slice of reserved cheese on top of each patty, cover with a lid, and cook until cheese is melted, about 1 minute. Transfer to baking sheet with buns.

Step 8

Spread a generous amount of chipotle mayo on cut sides of buns. Build burgers with shredded iceberg lettuce, 2 patties, sliced red onion, and sliced heirloom or beefsteak tomato. Sprinkle tomato with salt, then close up burgers.