Young leaves are tender, mild and highly nutritious in salad or as cooked greens. Very easy to grow and very fast growing. Best when young and tender. Mild flavor (bland), so they absorb the flavor of whatever you cook them with.
Tyfon was developed from a cross between a stubble turnip and a Chinese cabbage. Now it's cold-hardy down to 10 F, stable OP variety.
It was originally bred for forage, and is used as a cover crop. Using full-size leaves as cut-and-come-again crops, Tyfon produces so much leaf per square foot that it can be used to feed a compost pile.