Place the ginger, garlic, shallot, red pepper flakes, fish sauce (or alternatives) and sugar in your food processor. Process until well combined, pulsing, until it becomes a paste. Scoop over the cabbage and using tongs or gloves, mix and massage the vegetables and the red pepper mixture together really well, until well coated. Pack the cabbage into a large quart glass jar or a crock, leaving 1-2 inches room at the top for juices to release. Add a little of the reserved brine to just cover the vegetables, pressing them down a bit. Place the whole cabbage leaf over top, pressing down – this should help keep the kimchi submerged under the brine. You can also use a fermentation weight placed over top the whole leaf to keep it submerged.