Begin by filling a medium saucepan with about an inch of water and bringing it to a gentle simmer over medium heat. Place a heatproof mixing bowl on top of the saucepan, ensuring it does not touch the water. In this bowl, add ½ cup of unsalted butter cut into pieces, allowing it to melt slowly as you prepare the other ingredients for your lime curd recipe.

While the butter melts, grab a mixing bowl and combine 1 cup of fresh lime juice, 1 tablespoon of lime zest, and 1 cup of granulated sugar. Crack in 4 large eggs, whisking everything together until the mixture is completely blended and has a slightly frothy appearance.

Once your butter is fully melted, carefully pour the lime mixture into the heatproof bowl, stirring gently to combine. Place the bowl over the simmering water, stirring continuously for approximately 6 to 9 minutes.

Grab a candy thermometer and carefully insert it into the curd mixture. Cook until the temperature reaches 190°F to 200°F.

Once your lime curd has reached the right temperature and texture, remove the bowl from the heat. Set a fine-mesh sieve over a clean jar and carefully pour the curd through it to strain out the zest and any egg bits.

Allow the strained lime curd to cool at room temperature for about 15 minutes. For short-term storage, refrigerate in an airtight container for up to a week.