How to Make It
In a small bowl, mash the softened butter with the herbs, 2 tablespoons of cashews, the almond meal and ginger. Season with salt and pepper. Using your fingers, loosen the skin of each chicken breast to form a pocket, then stuff with a generous tablespoon of the ginger-nut butter. Season the chicken with salt and pepper and refrigerate until the butter is firm, about 20 minutes.
Preheat the oven to 400°. In a large cast-iron skillet, heat the oil. Add the chicken breasts skin side down and cook over moderately high heat until well browned, 5 minutes. Turn the breasts and cook for 3 minutes. Transfer the skillet to the oven and bake the chicken for 8 to 10 minutes, until just cooked through. Transfer to a platter and keep warm.
Melt 1 tablespoon of the butter in the skillet. Add the shallot and cook over moderately high heat, stirring, until softened, 1 minute. Add the wine and cook, scraping up the browned bits, until nearly evaporated, about 3 minutes. Add the stock and simmer until reduced to 1/2 cup, about 9 minutes. Whisk in the remaining 3 tablespoons of butter and season with salt and pepper. Strain the sauce into a bowl.
Spoon the sauce onto plates. Set the chicken on top, sprinkle with cashews and serve.