Heat 1 tbsp olive oil in a small skillet over medium heat. Add the thinly sliced onion and a pinch of salt. Cook, stirring occasionally, until the onion softens and begins to brown, about 8–10 minutes.

Add 2 tbsp brown sugar and stir to coat the onions. Continue cooking until the sugar melts and the onions caramelize, about 4–6 minutes more.

Stir in 1 tbsp apple cider vinegar and 1 tsp balsamic vinegar. Cook for 1–2 minutes to deglaze and let the mixture reduce slightly. Taste and season with 1 tsp salt and 1/2 tsp black pepper; adjust sweetness or acidity if needed. Remove from heat and let cool to room temperature. Yield: about 1/2 cup.

PS. Sauce

In a small bowl combine 4 tbsp mayonnaise, 1 tbsp ketchup, 1 tsp Dijon mustard, 1 tsp Worcestershire sauce, 1 tsp garlic powder, 1 tsp smoked paprika and 1 tsp hot sauce (optional). Whisk until smooth and homogenous.

Taste and adjust seasoning — add more hot sauce for heat or a touch more ketchup for sweetness. Refrigerate until ready to assemble. Yield: about 1/3 cup.

Shoestring Fries

Peel the russet potatoes (optional) and cut into very thin matchsticks (shoestring). Rinse the cut fries thoroughly under cold water until water runs clear to remove excess starch.

Dry the fries thoroughly on clean kitchen towels or paper towels — moisture will cause oil to splatter and prevents crisping.

Pour enough oil into a heavy pot or deep fryer to create a 2–3 inch deep frying pool and heat to 325°F (165°C). Fry the potatoes in batches for 3–4 minutes until they are soft but not colored. Remove with a slotted spoon and drain on paper towels.

Increase oil temperature to 375°F (190°C). Fry the blanched fries again in batches until golden and crisp, about 2–3 minutes. Drain on paper towels and immediately season with 1 tsp fine sea salt. Keep warm while you cook the burgers.

Burger

Divide the 1 lb ground barley-fed beef into two equal portions (about 8 oz each). Form each portion into a loose round patty about 3/4-inch thick and slightly wider than the buns. Handle the meat minimally and do not overwork.

Season both sides of each patty with 1/2 tsp kosher salt and 1/2 tsp freshly ground black pepper (total listed in ingredients). Press a slight indentation in the center of each patty with your thumb to reduce doming while cooking.

Preheat a heavy skillet or cast-iron pan over medium-high heat and lightly oil the surface or brush with a little oil. When hot (surface should shimmer), add the patties. Cook without moving for 3–4 minutes until a deep brown crust forms.

Flip the patties and immediately place a slice of cheddar on each patty. Cook another 3–4 minutes for medium doneness (internal temp ~ 130–135°F / 54–57°C). Cook longer if you prefer to medium-well. During the last minute, spoon about 1 1/2 tbsp PS. sauce onto each bun bottom (or spread after toasting).

While patties rest for 2–3 minutes, butter the cut sides of burger buns and toast them face down in the hot skillet until golden, 30–60 seconds.

To assemble: Spread remaining PS. sauce on the top bun as desired. Place the cheese-topped patty on the sauce-covered bottom bun, add 1 tbsp onion chutney on top of the cheese, then layer 3 pickle slices and 1 baby cos leaf (repeat for second burger). Finish with the top bun.

Serve each burger with a portion of shoestring fries and a side of ketchup for dipping.