Ingredients
For the horseradish sauce:
  • ¾ cup crème fraiche, or sour cream
  • ¼ cup prepared horseradish
  • ¼ cup fresh chives, finely chopped
  • 2 tablespoons Worcestershire sauce
  • 1 tablespoon coarsely ground black pepper
For the burger stacks:
  • 3 tablespoons butter
  • 1 large white onion, sliced
  • Salt
  • 4 brioche burger buns, split
  • 2 tablespoons canola, safflower, or peanut oil
  • 1 ¼ to 1 ½ pound very thinly sliced boneless rib eye (look for beef sliced for Philly cheesesteaks, a.k.a. top round steak, in the packaged meat section; or in a pinch, use very thinly sliced rare deli roast beef)
  • Pepper
  • Granulated garlic
  • Bread-and-butter pickle slices
  • 8 ounces extra-sharp white cheddar, coarsely grated
  • 2 cups watercress or upland cress, leaves and tender sprigs only
Yield
Serves: 4
Preparation

Preheat the broiler. In a medium bowl, stir all the sauce ingredients until blended.

In a medium skillet, melt 1 tablespoon butter over medium-low to medium heat. Add the onion; season with salt. Cook, stirring often, until the onion is softened, about 10 minutes. Add ½ cup water. Cook, stirring occasionally, until the water evaporates, about 5 minutes. Remove the onion from the heat.

In a small bowl, microwave the remaining 2 tablespoons butter on high until melted, 30 to 40 seconds.

Toast the buns under the broiler until golden brown, 1 to 3 minutes. Brush the cut sides of the buns with melted butter.

Heat a large griddle or cast-iron skillet over medium-high to high. Add a drizzle of the oil. Working in batches, add the beef in a single layer; season with salt, pepper, and granulated garlic. Using tongs to turn the beef, cook until browned and crisp, 1 to 2 minutes per batch; add more oil between batches. Transfer the beef to a platter; tent with foil to keep warm.

Divide the onion among the bun bottoms. Top each with some pickles, a few slices of warm beef, some sauce, and the grated cheese. Repeat the layering 2 more times with the beef, sauce, and cheese. Top with some cress and more sauce. Set the bun tops in place.