Roughly chop the kimchi into small pieces and finely slice the spring onions. Add these to a large mixing bowl along with a tablespoon of the reserved kimchi brine. Add the plain flour, water and sugar, then mix well to combine everything.
Preheat a large non-stick frying pan over a medium heat, add 1-2 tablespoons of vegetable oil and allow to the oil to warm up. Scoop the kimchi batter into the hot pan and spread it around with the back of a spoon until you have an even layer that covers the pan like a large pancake. Turn down the heat a little and allow to cook on this side for 4-5 minutes, checking occasionally and turning down the heat if it’s burning. It’s important to really let that first side crisp up and cook properly and you’ll notice patches of the top of the batter starting to dry out.
Confidently flip the pancake (if you can!). If not, slide the pancake onto a plate that roughly fits inside the frying pan and, once the pancake is on the plate, carefully place the frying upside down over the top to cover it and flip it this way.
Continue cooking on the second side for 4-5 minutes, until the pancake is golden and crispy and doesn’t seem wet or overly soft to the touch.]
Top with the extra spring onions, coriander, sesame seeds and chilli oil. Serve and enjoy warm!