To make Devil’s steak sauce:
Boil balsamic vinegar in a large, wide frying pan over high until reduced by half, 2 to 3 min. Add remaining ingredients to pan. Continue boiling, whisking often, until slightly thickened and reduced to 1 cup, 2 to 4 more min. Cool completely.
To make Five-alarm burgers:
Preheat barbecue to medium. Whisk 1/3 cup Devil’s Steak Sauce with 1/3 cup dried bread crumbs, 2 sliced green onions, 1 finely chopped seeded jalapeno and 1/4 tsp salt in a large bowl. Crumble in 450 g ground beef. Mix until just combined. Do not over-mix. Shape into 4 burgers, each about 1 in. thick. Oil grill, then barbecue burgers, with lid closed, until cooked through, 5 to 6 min per side.