Construct the Engineered Fat Matrix: Place chicken thighs in food processor and pulse in 1-second bursts for 12-15 pulses total until coarsely ground (rice-grain sized pieces). Transfer to large bowl. Grate frozen butter on large holes of box grater. Add grated butter, Greek yogurt, ginger paste, garlic paste, and salt to ground chicken. Fold gently with cold hands just until distributed—mixture should look shaggy and barely cohesive. Divide into 4 portions (approx. 6 oz each) and shape into very loose balls. Freeze on parchment-lined plate for exactly 10 minutes.
Create the Ultra-Reduced Makhani Glaze: In small saucepan over medium heat, melt 2 tbsp butter. When foam subsides, add sieved tomato puree, Kashmiri chili powder, garam masala, and crushed fenugreek leaves. Reduce heat to medium-low and simmer uncovered for 12 minutes, stirring every 90 seconds. Add heavy cream in thin stream while whisking constantly. Continue simmering for 8 additional minutes, stirring constantly. Final glaze should coat spoon like thick honey. Remove from heat and keep warm.
Prepare Kachumber Slaw: Thinly slice red onion and cucumber (use mandoline if available). Combine with chopped cilantro, lime juice, and salt in small bowl. Toss gently and set aside (make no more than 5 minutes before assembly).
Execute Cryo-Shock Smash Technique: Preheat cast-iron griddle over high heat for 5 minutes until surface reaches 450°F (verify with infrared thermometer). Do not add oil. Remove patty balls from freezer (should be 28-30°F internal temp). Place one ball on griddle and immediately press with burger press or parchment-covered spatula, applying firm steady pressure for exactly 3 seconds to flatten to ⅓-inch thickness. Do not adjust or re-smash. Cook undisturbed for 90 seconds—do not touch. Lacy edges will form and char. Slide spatula firmly under patty, scraping to release crust, and flip in one motion. Place cheese slice on cooked surface immediately. Cook second side for 60 seconds. Transfer to wire rack.
Glaze the Patties: While patty rests on wire rack (still hot), use silicone brush to generously paint warm Makhani glaze over entire top surface including cheese and edges. Let glaze set for 30 seconds while it cools and thickens. Repeat glazing and cooking process for all 4 patties.
Toast and Assemble: Slice brioche buns and toast cut-side-down on griddle for 45 seconds until golden-brown. Assembly per burger: Bottom bun (toasted side up) → 1 tsp Makhani glaze spread thin → ¼ cup kachumber slaw → Makhani-glazed patty with cheese → top bun interior brushed with 1 tbsp Makhani glaze → place top bun glaze-side-down. Press gently to integrate. Rest 60 seconds before serving.
