Mix together the sugar, water, soy sauce, mirin, ginger, coriander and freshly ground white pepper in a small skillet or saucepan and bring to a boil. Reduce the heat and simmer briskly, stirring occasionally, for 15 to 18 minutes, depending on the heat, until syrupy. Add the vinegar and orange juice; stir and cook 1 minute longer. Remove from the heat and set aside.

In a large bowl, mix together the pork, scallions, cilantro, egg, 2 tablespoons sesame oil, soy sauce, and freshly ground white pepper. Chill for 30 minutes. Roll into balls — about 1 1/2 tablespoons each — then flatten to patties. You should get about 20.

In a large skillet over medium heat, add 2 teaspoons vegetable oil and 2 teaspoons sesame oil. Add the tatsoi leaves and cook, tossing, until gently wilted. Lower heat until ready to serve.

Put a large nonstick skillet on medium-high heat; when hot, cover the bottom with vegetable oil. Place patties in the skillet and cook, turning once, until browned and cooked inside, about 2 minutes per side. If your pan isn’t large enough to cook all the patties at once, do it in two batches. Remove from the pan and set on paper towels to drain.

Divide the tatsoi among four serving bowls and sprinkle with sesame seeds. Place five patties in each bowl, drizzle with sauce, and top with cilantro leaves and sliced scallions.