EnlargeCredit: Cafe FernandoThe traditional recipe calls for lemon juice to add acidity (which also prevents discoloration), but I like to add the whole lemon. That way, the aromatic zest is completely absorbed by the celeriac. In addition to lemon, orange and/or tangerine adds a sweet touch. I also like to add either a quince or a green apple to cheer it up. Feel free to experiment and enjoy!