Nopa Cheeseburger Recipe

Place thinly sliced red onion in a heatproof jar or bowl.

In a small saucepan combine apple cider vinegar, water, sugar, kosher salt, peppercorns and bay leaf. Bring just to a simmer over medium heat, stirring until sugar dissolves (about 2–3 minutes). Remove from heat.

Pour hot pickling liquid over the sliced onions, pressing to submerge. Let cool to room temperature, then cover and chill for at least 30 minutes (best if made 1–2 hours ahead or overnight). Discard bay leaf before serving.

In a small bowl whisk together mayonnaise, prepared horseradish, lemon juice, Dijon mustard, grated garlic, kosher salt and black pepper until smooth and well combined.

Taste and adjust seasoning — add more horseradish for heat or lemon for brightness. Cover and chill for at least 15 minutes to let flavors meld.

Cut the scrubbed Kennebec potatoes into 1/4–1/2 inch sticks. Rinse in cold water until the water runs clear to remove excess starch, then pat completely dry with a towel.

In a heavy-bottomed pot or deep fryer, heat oil to 325°F (160°C). Fry potatoes in batches until tender but not browned, about 4–6 minutes per batch. Remove with a slotted spoon to a paper towel-lined tray and let rest 5 minutes.

Increase oil temperature to 375°F (190°C). Return fries to the hot oil in batches and fry until golden and crisp, about 2–3 minutes. Drain on fresh paper towels, immediately season with kosher salt and black pepper. Keep warm in a low oven while finishing burgers.

Divide the 1 lb of beef into four 4-ounce portions. Gently form each portion into a loose patty about 3/4 inch thick, making a shallow dimple in the center of each patty to help it cook evenly. Do not overwork the meat.

Season both sides of each patty with sea salt and black pepper just before cooking.

Heat a cast-iron skillet or griddle over medium-high heat until very hot. Add a thin film of neutral oil or spray. Place patties on the hot surface, leaving space between them. Cook undisturbed for 3 minutes to develop a crust.

Flip the patties and immediately top each with a slice of cheddar if using. Cook 2–3 minutes more for medium-rare to medium (internal temp 130–140°F / 54–60°C). Adjust time for desired doneness.

While patties finish, melt butter in another skillet over medium heat and toast the cut sides of brioche buns until golden, about 1 minute per side.

To build each NOPA Cheeseburger: spread about 1 tablespoon horseradish aïoli on the bottom bun, add a lettuce leaf, place the hot cheeseburger patty, top with a slice of tomato and a generous spoonful of pickled red onions. Spread a little more aïoli on the top bun and close the sandwich.

Serve immediately with a portion of Kennebec fries on the side and extra aïoli for dipping.