Tatsoi is a gently cabbagey asian green that looks like bok choy with longer, thinner stems and smaller, rounder leaves. Bok choy is another asian green, with thick white stems and long green leaves. It is typically found in wonton soup.
The two together made a nice replacement for kale, in a recipe from Cuisine at Home's Slow Cooker Menus that is meant to be served alongside Slow Cooker Asian Short Ribs and rice. This was just right with the ribs and much more interesting than sautéed greens with a minced shallot, which is how I usually prepare them.
Sautéed Tatsoi and Bok Choy (adapted from Slow Cooker Menus p. 63):
This takes 10 minutes to prepare and cook.
It serves 4.
1 bunch bok choy
1 bunch tatsoi
1 Tablespoon olive oil
2 Tablespoons minced garlic
1/2 teaspoon red pepper flakes
1/4 cup chicken stock
2 Tablespoons toasted sesame seeds
Toasted sesame oil
Trim the bottom end of the stems from both vegetables, to separate the stems. Slice the stems into 3/4 inch pieces and the leaves into 3/4 inch ribbons, then wash and spin them dry in a salad spinner. It's fine if some water is still clinging to them.
Heat the olive oil in a large skillet or wok over medium high heat. When it shimmers, add the garlic and red pepper flakes. Stir for thirty seconds. Add the greens and broth, stir until kale is as wilted as you like it, about five minutes.
Season with sesame oil and salt, then sprinkle the seeds over the top.