- 1 large onion, finely chopped
- 3 tablespoons olive oil
- 1 1/2 lb boiling potatoes
- 8 cups water
- 1/2 lb Spanish chorizo (spicy cured pork sausage), cut into 1/2-inch pieces
- 3/4 lb lacinato or regular kale, center ribs discarded and leaves cut crosswise into thin slices
- Cook onion in oil in a 5-quart pot over moderate heat, stirring occasionally, until pale golden. Meanwhile, peel potatoes and cut crosswise into thin slices. Add to onion and cook, stirring occasionally, 4 minutes. Add water and salt to taste and simmer until potatoes are very tender, about 15 minutes.
- Cook chorizo in a large nonstick skillet over moderately high heat, stirring occasionally, until browned, about 5 minutes. Transfer to paper towels to drain.
- Coarsely mash potatoes in pot with a potato masher (do not drain). Stir in chorizo and simmer 5 minutes. Stir in kale and simmer until just tender, 3 to 5 minutes. Season with salt.