Preheat the oven to 350 degrees F. Toss the nuts, melted butter, rosemary, brown sugar and cayenne in a large bowl until combined. Spread the coated nuts in a single layer on a rimmed baking sheet.
Bake the nuts until fragrant and toasted, about 10 minutes. Let cool completely before serving.
Photograph by David Malosh
Recipe courtesy of Marc Murphy for Food Network Magazine