Soak wooden toothpicks or skewers in warm water for about 30-60 minutes before cooking. (Soaking will prevent the wooden skewers from burning in the oven! It can help to place a glass on top of the skewers to keep them submerged in the water.)
Preheat oven to 425°F (220°C).
Cut potatoes ~⅛-inch thick (or thinner) using a mandolin. Gently dry russet potato slices between paper towels to remove excess moisture
In a bowl, combine oil, fresh herbs, salt, and pepper. Add potato slices and toss until coated evenly.
In a sprayed muffin tin, layer russet potato slices and sweet potato slices. Stack to the top of each muffin cup, or about ½ inch above the rim.
Pat wooden skewers/toothpicks dry (so they’re not dripping wet) and skewer each potato stack.
Bake 25-30 minutes, until golden and crispy.
Allow to cool ~5 minutes before removing with a butter knife or offset spatula.
Sprinkle with Parmesan, serve, and enjoy!
Yields 12 russet and sweet potato stacks.
*Omit Parmesan for vegan, vegetarian, paleo & dairy-free.