Storage: Best eaten immediately while warm and crispy. Leftovers can be stored in an airtight container at room temperature for up to a day, but may lose some crispness.
Substitutions: You can use regular granulated sugar if demerara is unavailable, though it won't have the same crunchy texture. Margarine works, but butter provides a richer flavor.
Tips: Keep a close eye on the toast under the broiler as sugar burns quickly. Use sturdy bread to prevent sogginess.
Variations: Add a dash of vanilla extract to the butter mixture for extra aroma, or sprinkle with chopped nuts before broiling.