How to Make It
In a small bowl, cover the dried currants with hot water. Let stand until softened, about 5 minutes; drain.
Meanwhile, in a large pot of boiling water, cook the kale until tender, about 5 minutes, then drain. When the kale is cool enough to handle, gently squeeze out any excess water. Coarsely chop the kale.
In a large, deep skillet, melt the butter in the olive oil. Add the onion and cook over moderately low heat, stirring occasionally, until softened, about 7 minutes. Add the chicken broth and blanched kale and toss thoroughly. Cover and cook over moderate heat, stirring a few times, until the kale is hot and sizzling, about 3 minutes. Stir in the currants, olives, lemon zest and lemon juice and cook, stirring constantly, until heated through. Season with salt and pepper and serve.