Heat a skillet over medium-high heat and sauté cashew nuts for 2-3 minutes. Set aside.
Steam kale for 5 minutes. Transfer it to a blender together with anchovies, garlic clove, freshly ground black pepper, olive oil and 1 tablespoon of toasted cashew nuts. Add mascarpone and blend untill creamy.
In the meantime, cook the Ravioli according to package instructions and drain, reserving 2 cups of the pasta cooking water.
Loosen kale pesto with reserved water till you reach a sauce-like consistency and pour it in a big bowl. Add cooked Ravioli, toss gently and serve sprinkled with remaining cashew nuts.