Core the cabbage and discard outer leaves, then cut the cabbage lengthwise into quarters.
Cut the quarters crosswise into 1 inch pieces.
Stem, seed, and mince the chili pepper.
Coarsely chop the scallions.
Transfer pieces to a large bowl and toss with 2 T of the salt, the chili peppers, and the scallions.
Place a weighted plate/bowl on top of the mixture, and let it stand at room temp for an hour.
Rinse and drain, squeezing out as much liquid as possible. Return cabbage to the empty bowl.
Zest lime, and squeeze juice into a separate cup to be used next.
Combine the sugar, water, lime juice, the remaining salt, and the vinegar in a medium pan over medium-high heat, stirring to dissolve the sugar and salt, then remove from heat. Let cool for 10 mins.
Discard outer leaves of the 4 lemongrass stalks and mince.
Peel and grate your ginger root.
Combine the lime zest, turmeric, ginger, lemon grass, and garlic in a blender or cuisinart, along with 1/2 cup of the still cooling vinegar mixture. Purée, adding more vinegar mix until it's smooth.
Add the remaining mixture to the blender and pulse several times to combine, then pour the blend over the drained cabbage. Add the fish sauce or additional salt, and your preferred hot sauce.
Mix well! It helped that this bowl had a lid.
Cool to room temp and serve, or cover in airtight container(s) and refrigerate for up to 4 weeks.