My reaction to seeing tatsoi at Waitrose (where it is on limited edition 3 for 2 sale) was, “what?!” We’ve all heard of pak choi, but it was the first time I had heard of this vegetable, grown in China since AD 500 and now grown worldwide. It may be more popular outside of than inside of China, since none of my relatives on the mainland have heard of it (in Chinese it is 塌菜, literally translated as ‘collapsing vegetable’). I cut the stalks in half and sautéed them like I do with most Chinese greens: with thin-sliced garlic and a splash of soy sauce, or with finely chopped chilli and ginger and a splash of soy sauce. It tastes slightly of mustard, and has no bitter taste. It has a stronger taste than pak choi. It costs around the same price but is twice as nutritious as pak choi. If ever there was a time to shift vegetable allegiances, it is now.