Preheat the oven to 350°. Spread the almonds on a large rimmed baking sheet and roast for 15 minutes, until browned; let cool. Reduce the oven temperature to 300°. Toss the almonds with the tamari, then toss with the butter. Roast the almonds for 10 minutes, stirring, until richly browned. Let cool. Season with salt and cayenne and serve.