For Korean BBQ Sauce
1/2 c. (plus 1 tbsp.) soy sauce
1/4 c. brown sugar
1 1/2 tbsp. sriracha
2 cloves garlic, minced
2 tsp. ginger
2 tbsp. (plus 2 tsp.) rice vinegar
2 tsp. crushed red pepper flakes
1 tbsp. cornstarch
1 tbsp. water
For Asian Slaw
1 c. Napa cabbage, shredded
1 purple cabbage, shredded
1 jalapeño, seeded and thinly sliced
1/4 English cucumber, thinly sliced
For the Burger
1 lb. ground short rib (other ground beef can be substituted)
2 tbsp. unsalted butter
3 sesame seed hamburger buns
In a medium saucepan over medium heat, combine ½ cup soy sauce, brown sugar, Sriracha, garlic, ginger, 1 tablespoon rice vinegar, and 1 teaspoon crushed red pepper flakes and bring to a boil. In a small bowl, stir together cornstarch and water and add to saucepan. Reduce heat to low and let thicken, 5 to 10 minutes.
Toss cabbage and jalapeño with 2 teaspoons rice vinegar, 1 teaspoon soy sauce, 1 teaspoon crushed red pepper flakes, and sesame seeds.
Toss cucumber with remaining tablespoon rice vinegar and a pinch of salt.
Form meat into three equal-sized patties. Brush one side with Korean BBQ sauce.
Heat cast-iron skillet over medium-high heat and melt butter. Add burgers sauced-side-down and brush other side with sauce. Cook 2 to 3 minutes per side for medium rare.
Build burgers by topping buns with cucumbers, patty, more Korean BBQ sauce, and slaw.