Dry-aged beef burger on a sesame brioche bun with caramelized onion jam

Whisk bread flour, sugar, kosher salt and instant yeast.

Mix hot tap water with cold milk so the liquid is no hotter than 100F; add and mix two to three minutes to a fairly smooth dough.

Add the butter one piece at a time, each fully emulsified before the next; mix about ten more minutes to strong gluten development.

Shape into a taut ball and proof in the oven with the light on at around 88 to 90F, turning the light off after about 20 minutes.

Halve the onions and slice across the poles on a mandolin.

Crowd the onions into a small pan with a tablespoon of butter; add a little water, cover and steam, then cook low and slow to deep golden brown.

Add a little balsamic reduction for acid and salt lightly.

Cut the dry aged trimmings down to fit the grinder; freeze about 20 minutes until firm outside; chill the grinder at least an hour; grind for a pebbly texture.

Divide the over-proofed dough into portions around 115 g, shape into buns and proof about another hour.

Brush with beaten egg yolk down to the parchment and sprinkle with black or white sesame seeds.

Bake, checking constantly; flip and rotate after 15 minutes.

Form half-pound patties in a ring mold.

Wrap the tough-crusted buns in aluminum foil to steam and soften while cooling.

Brush the cut buns with melted dry aged beef tallow and toast in a skillet.

Salt the patties heavily and sear in a skillet with hardly any fat until deeply crusted; flip and salt the other side.

Add double American cheese, then finish in the oven to 125 for medium rare.

Toast the buns in the beef fat, spread caramelized onions on the bun, and assemble.