Yield: 4-6 burgers
2 pounds ground beef chuck
2 teaspoons kosher salt
1 1/2 teaspoons freshly-ground black pepper
1 cup thinly-sliced celery stalks, cut on a sharp bias
1/3 cup celery leaves
3/4 of a small sweet-tart apple (such as Pink Lady, Braeburn or Honeycrisp), cored and very thinly sliced (about 1 cup)
10-15 paper-thin slices of jalapeño (will vary with heat of jalapeno), or to taste
2 tablespoons grainy mustard or 1 tablespoon Dijon mustard
2 teaspoons apple cider vinegar
1 teaspoon honey, or to taste
Pinch of salt
2 tablespoons olive oil
High-heat vegetable oil, for grilling
4-6 thick slices sharp white cheddar
Grilled or toasted hamburger buns
In a large bowl, season the ground beef with the salt and pepper. Use your hands to mix thoroughly. Divide the seasoned beef into 4 to 6 balls of equal size, depending on how large you want your burgers to be; ideally, your hamburger patties will be about 1/2-inch wider than your burger buns. Form the balls into patties, making a 1/2-inch depression in the center of each to account for the fact that the burgers will swell as they cook.
Light 1 chimney’s-worth of charcoal. When hot and glowing, pour out the charcoal on one side of your grill. Place the cooking grate in place, close the lid and allow the grill to preheat for 5-10 minutes.
If using a gas grill, set half of your burners to high, close the lid and allow the grill to preheat for at least 10 minutes.
While the grill is preheating, make the slaw. In a medium bowl, combine the celery, celery leaves, apple and jalapeño. In a small bowl, whisk together the mustard, vinegar, honey and salt. Gradually whisk in the olive oil until the vinaigrette is emulsified. Dress the celery-apple mixture with the vinaigrette. Taste and adjust seasoning, adding a bit more honey if your apples are quite tart. Set aside.
When the grill is hot, clean the grill grate and brush it generously with the vegetable oil. Place the burgers on the hot side of the grill, close the cover, leaving vents open, and cook, turning occasionally, until grill marks appear and an instant-read thermometer inserted into the center of each burger register 110°F, about 5 minutes. Place a slice of cheese on top of each burger and continue to cook until the cheese is melted and the burgers register 125°F for medium rare or 13o°F for medium, 2-3 minutes longer. Transfer the burgers to a sheet-pan or large plate to rest. If desired, toast the buns on the grill.
To serve, place the grilled burgers on a bun and top with a generous amount of the slaw. Serve hot.