For the spicy mayonnaise:
1 cup mayonnaise
1 tablespoon soy sauce
3 tablespoons hot chili sauce, ideally Sriracha
For the scallion salsa:
1/2 cup soy sauce
2 tablespoons water
1/4 cup sugar
2 tablespoons gochugaru (Korean red-pepper flakes)
2 tablespoons grapeseed oil
2 tablespoons sesame oil
3 tablespoons rice vinegar
2 tablespoons mirin
1 tablespoon sesame seeds
2 bunches scallions, cleaned, dried and sliced on the bias
Unsalted butter & 6 soft hamburger buns or rice
In a large, nonreactive bowl, combine the soy sauce, sugar, garlic, sesame oil, sake, mirin, pear, carrot, onion and apple juice. Add the sliced brisket, stir to combine, cover tightly and place in the refrigerator overnight or for at least six hours.
Meanwhile, in a small, nonreactive bowl, combine the mayonnaise, soy sauce and hot chili sauce and stir to combine. Taste and adjust flavors, then cover and store in the refrigerator until ready to use.
When you are ready to make the sandwiches, set one very large sauté pan (or two large ones) over high heat. Using tongs, lift meat from marinade in batches, allow to drain well, then cook, turning occasionally until the excess liquid has evaporated and the edges of the beef have started to crisp.
Meanwhile, combine all the ingredients for the salsa except for the scallions, then stir to combine.
Toast and butter the hamburger buns. Spread spicy mayonnaise on the buns, and using tongs, cover one side of each set of buns with bulgogi. Add a large pinch of scallions on top of each burger and drizzle with the dressing.