- 3 cups fresh corn kernels (from 5 ears)
- 5 tomatillos (3/4 pound), husked and finely chopped
- 3 jalapeños, seeded and finely chopped
- 2 cups apple cider vinegar
- 1 large onion, finely chopped
- 1 red bell pepper, finely chopped
- 1/2 cup sugar
- 1 teaspoon yellow mustard seeds
- 1 teaspoon celery seeds
- 1/2 teaspoon coriander seeds
- 3 pounds skirt steak, cut into 1/4-inch dice and chilled
- Freshly ground pepper
- 3 ounces creamy blue cheese, such as Cabrales
- 6 sourdough rolls, split and lightly toasted
- In a large saucepan, combine the corn, tomatillos, jalapeños, vinegar, onion, bell pepper, sugar and the mustard, celery and coriander seeds. Bring to a boil; simmer over moderate heat until thickened, 40 minutes. Let cool and season with salt.
- Light a grill. Working in small batches, put a handful of diced skirt steak in a food processor and pulse about 4 times, until very finely chopped. Transfer to a bowl and repeat with the remaining skirt steak. Pat the mixture into 6 burgers.
- Season the burgers with salt and pepper and grill over a hot fire until medium rare, 3 minutes per side. About 1 minute before the burgers are done, place the blue cheese neatly on top of them. Set a burger on the bottom half of each roll, spoon some relish onto each, close the sandwiches and serve.
The cooked and cooled tomatillo-corn relish can be refrigerated for up to 1 week.