Toast the walnuts in a dry skillet until lightly browned; let cool. Pulse in a food processor until finely ground.
Add the kale and 1/4 teaspoon salt and pulse until finely chopped.
Add the parmesan and pulse to combine.
Slowly pour in the olive oil, pulsing to incorporate. Transfer the pesto to a bowl. You'll have about 1 cup pesto; use about 1/2 cup for 1 pound pasta.
Photograph by Kana Okada
Recipe courtesy Food Network Magazine