Preheat oven to 300°. Melt butter in shallow roasting pan. Spread pecans evenly in one layer and bake for 30 minutes or just until brown. Watch carefully for signs of scorching and stir several times during baking. Combine soy sauce and cayenne. Remove pecans from oven and mix with soy and cayenne, coating evenly. Spread on paper towels to cool. Store in sealed container at room temperature.