Lime makes for a delicious curd. Don't expect it to be green: The yolks will inevitably turn your curd a luscious yellow.

1. Place lime zest and sugar in a small bowl. Work the zest into the sugar with your fingers, until the sugar is yellow-green and aromatic.

2. Using a mixer, cream the butter in a separate medium bowl, then beat in the sugar mixture.

3. Add in eggs, one at a time, beating well after each addition. Add in lime juice and salt, and mix until thoroughly combined.

4. Heat mixture over medium-low heat until thickened, about 10 minutes, or until it reaches 170°F.

5. Remove from heat and allow to cool. Refrigerate, covered, until needed.