Mak-kimchi, "easy kimchi," is napa cabbage cut into bite-size pieces before seasoning, which makes it much quicker than whole-head kimchi. This keto version skips the usual rice porridge and sugar.
Cut the cabbage into 2-inch pieces. Toss with the salt in a large bowl and let sit for 1 1/2 to 2 hours, tossing every 30 minutes, until the thick parts bend without snapping.
Rinse the cabbage three times in cold water and drain well for 20 minutes.
Mix the gochugaru, fish sauce, salted shrimp, allulose, garlic, ginger and onion into a paste. Add the daikon and scallions.
Wearing gloves, toss the cabbage with the paste until every piece is coated. Pack tightly into clean jars, pressing out air and leaving 2 inches at the top.
Leave at room temperature for 1 to 2 days until it smells tangy and bubbles appear, then refrigerate. It continues to develop flavor for weeks.
Notes
Tip: Press down on the kimchi with a clean spoon each day while it ferments at room temperature, so the cabbage stays submerged in its juices.