Parlour Patty Melt* Recipe

Heat 1 tablespoon olive oil and 1 tablespoon butter in a heavy skillet over medium heat until shimmering.

Add the thinly sliced onion and a pinch of salt. Cook, stirring occasionally, until softened, about 8–10 minutes.

Reduce heat to medium-low, add 1/2 teaspoon granulated sugar, and continue to cook, stirring every few minutes so they brown gently and don’t burn, until deeply golden and jammy, about 20–25 more minutes.

Stir in 1 teaspoon balsamic vinegar at the end, cook 1 minute more to deglaze, then remove from heat. Reserve 3 tablespoons for the Carmie sauce and the remainder for sandwiches.

In a small bowl combine 1/4 cup mayonnaise, 2 tablespoons sour cream, 1 teaspoon Dijon, 1/2 teaspoon Worcestershire, 1/2 teaspoon lemon juice, 1/4 teaspoon salt and 1/4 teaspoon black pepper.

Stir in 3 tablespoons finely chopped caramelized onion until evenly incorporated. Taste and adjust seasoning. Refrigerate until ready to assemble.

Thinly season the 8 oz of sliced steak with 1 teaspoon salt and 1/2 teaspoon black pepper; toss to coat.

Heat a clean heavy skillet or cast-iron pan over medium-high heat with 1 tablespoon butter. When hot, add the seasoned steak in an even layer and sear briefly, 1–2 minutes per side, just until browned but still juicy. Remove from pan and let rest 2 minutes; if slices are large, chop coarsely into bite-sized pieces.

Butter one side of each bread slice lightly with the softened butter (about 1 tablespoon total per sandwich, divided). The buttered sides will contact the skillet.

Spread a generous tablespoon of Carmie sauce on the unbuttered side of two bread slices (these will be the inside of each sandwich).

On each sauced slice layer: 2 slices American cheese (or mild cheddar), half of the warm sliced steak (about 4 oz), 2 slices Swiss cheese, and a spoonful (~1–2 tablespoons) of remaining caramelized onions. Top each with the second bread slice, buttered side out.

Heat a skillet over medium heat. Place sandwiches in the skillet and press gently with a spatula or a grill press. Cook until golden brown and cheese begins to melt, about 3–4 minutes per side. Lower heat if bread browns too quickly. Total cook time ~6–8 minutes.

If desired, cover the pan with a lid for the last 1–2 minutes on the second side to help the cheese fully melt.

Remove sandwiches from pan and let rest 1 minute, then cut in half diagonally. Serve with dill pickle slices, extra Carmie sauce on the side if desired.