Remove the outer leaves of the cabbage and set one aside for later.
Cut the cabbage into quarters and remove the core.
Shred the cabbage and place it in a large bowl.
Sprinkle the cabbage with 1 tablespoon of kosher salt.
Massage the cabbage with clean hands for about 5 minutes. Cover with a tea towel and let it rest for 20–30 minutes.
Repeat the massaging and resting process two more times. The liquid released is called brine.
Spoon the cabbage and brine into a 2-quart mason jar, packing it down firmly.
Use a wooden spoon or stomper to press the cabbage until the brine rises above it.
Fold the reserved cabbage leaf and place it on top to keep everything submerged.
Add a fermentation lid or a regular canning lid.
Store the jar in a cool, dark place away from direct sunlight.