How to Make It
Bring a large pot of salted water to a boil. Add the mustard greens and cook for 2 minutes. Add the spinach and cook for 30 seconds. Drain the greens, transfer to a food processor and puree. Sprinkle the cornmeal over the greens and pulse briefly to combine. Transfer the pureed greens to a bowl.
Add the garlic, jalapeños and ginger to the food processor and finely chop. Add the onions and finely chop.
In a large nonstick skillet, heat the oil. Add the garlic-onion mixture and cook over moderate heat, stirring occasionally, until lightly browned, about 7 minutes. Add the pureed greens and cook for 4 minutes, stirring occasionally; add about 1/4 cup of water if the greens look dry. Season with salt and serve.