To make the dipping sauce, in a small bowl mix together the white sugar, sesame oil, rice wine vinegar and soy sauce. Set aside.
In a large bowl, mix together the chopped kimchi, kimchi liquid, soy sauce, plain flour, egg, two thirds of the sliced scallions, and black pepper, until well combined.
Place a large pan over medium-high heat and add the vegetable oil.
Pour the kimchi batter into the pan, and smooth over with a spoon to create a large pancake.
Sprinkle the pancake with the sesame seeds.
Cook the pancake until crispy and golden brown underneath, then carefully flip using two egg-flips.
Cook the other side of the pancake until crispy and golden brown once again.
Remove the pancake from the pan, cut into eight wedges, and place onto a serving plate. Garnish with the leftover sliced scallions and enjoy the kimchi pancake with the soy dipping sauce.