Arrange a rack in the center of the oven. Preheat the oven to 325° Fahrenheit (165° celsius).
In a spice or coffee grinder, combine salt and fresh rosemary leaves. Grind until the rosemary is finely distributed throughout the salt. (If using dried rosemary powder, Skip to step 3.)
In a small bowl, combine rosemary salt, sugar, black pepper and cayenne (or cinnamon), if using. Rub the rosemary salt into the mixture until evenly distributed. Set aside.
In a large mixing bowl, vigorously whisk the egg white until frothy. Add the nuts and toss until evenly coated in egg white. Add the sugar and seasoning mixture and toss again until evenly coated.
Prepare a half sheet pan with non-stick cooking spray. Arrange the coated nuts on the sheet pan in a single layer. Bake for 10 minutes. Carefully stir the nuts, rotate the pan in the oven and continue baking for 10 - 15 minutes or until the nuts are toasted and aromatic.
Allow the nuts to cool completely. Use your hand to break up clumps of nuts that have stuck together. Enjoy by the handful.
