In a mixing bowl, combine all-purpose flour, baking powder, and salt. Gradually stir in water until achieving a smooth batter. Fold in chopped kimchi and kimchi juice. If using an egg, beat it separately and mix it in. Let the batter rest for about 5 minutes.

Heat a non-stick skillet over medium heat for about 2 minutes. Drizzle vegetable oil to coat the bottom evenly.

Pour a generous amount of batter into the skillet, forming a 6-inch pancake. Cook for 2-3 minutes until edges are golden brown, then flip and cook the other side.

Transfer pancake to a plate and repeat with remaining batter, adding more oil as needed. Serve hot, optionally topped with extra chopped kimchi.