Let's not get ahead of ourselves: You can make lemonade with any lemon. But these were specifically bred from a lemon and mandarin orange with the hopes of being the perfect lemon for sweet yet sour lemonade (via Frieda's). The sweetness of the mandarin offsets the bitterness of the lemon (most likely a Lisbon or Eureka). And while they were specifically designed with lemonade in mind, you can really substitute them for a "true" lemon whenever you want. We think using Lemonade lemons for citrus cakes and desserts would be almost too outstanding to manage.