How to Make It
In a large glass or ceramic bowl, toss the shredded cabbage with 1 tablespoon of salt. Weight down with a heavy plate topped with canned goods and refrigerate the cabbage for 1 hour.
Using a sharp knife, peel the grapefruit, removing all of the bitter white pith. Working over a bowl, cut in between the membranes to release the sections. Squeeze 2 tablespoons of the juice from the membranes into a small bowl. Whisk in the oil and lemon juice and season with salt and pepper.
Squeeze the cabbage dry and transfer it to a large bowl. Add the kohlrabi and vinaigrette and toss well. Add the grapefruit sections and shredded mint and toss again. Mound the salad on plates, garnish with mint leaves and serve.