- 3 lemons
- 1 ½ cups sugar
- ¼ pound (1 stick) unsalted butter, softened to room temperature
- 4 extra-large eggs
- ½ cup lemon juice (3–4 lemons – you can use the same ones from above, after you follow step #1 below)
- 1/8 teaspoon kosher salt
- Using a vegetable peeler, remove the zest from the whole lemons. (Try to avoid peeling any of the bitter white pith as you remove the zest.)
- Fit a food processor with a metal blade. Place the zest in the bowl of the processor along with the sugar. Pulse until the zest is very finely chopped and fully incorporated into the sugar.
- In the bowl of a stand mixer, cream the butter until light and fluffy. Add the sugar and lemon mixture and beat to mix well.
- Add the eggs, one at a time, mixing well after each addition. Add the lemon juice and salt and mix again.
- Secure a candy thermometer to the side of a medium saucepan. Pour the lemon mixture into the saucepan and over low heat, stirring constantly, cook until thickened (around 170 degrees – the mixture will be just below a simmer).
- Remove the curd from the heat and pour into a bowl. Cover the bowl with a large piece of plastic wrap, pushing the plastic down to touch the top of the curd. (This will prevent a skin from forming on the curd as it cools.)
- Refrigerate overnight to thicken further.