makes 1 ½ cups
3 lemons (or any other acidic fruit or liquid)
½ cup sugar
8 tablespoons (1 stick) butter, very cold
½ teaspoon kosher salt
1. Using a Microplane or the finest-toothed side of a box grater, zest the lemons/limes/grapefruit. Do your best to grate only as far down as the yellow part of the skin; the white pith has less lemon flavor and can be bitter. If your bitter liquid doesn’t have a peel to zest, no worries! Squeeze juice from the lemons/limes/grapefruit, or simply measure out ⅓ cup juice of whatever flavor you’re rocking.
2. Put the sugar, zest (if you have it), juice and eggs in a blender (lid on!) and blend on low until you have a bright-yellow mixture. Transfer the mixture to a medium pot or saucepan. Clean the blender canister and put cold butter and salt inside, set aside.
3. Heat the mixture over low heat, whisking regularly. As it heats up, it will begin to thicken; keep a close eye on it. Once it boils, remove it from the stove and transfer it to the blender with the butter and salt already inside. Lid on! Blend until the mixture is thick, shiny, and super-smooth.
4. Pour the mixture through a fine-mesh sieve into a heatproof container, and put in the fridge until the curd has cooled completely, at least 30 minutes. Refrigerate the curd for up to 2 weeks (don’t worry, it will be consumed in 48 hours, even if you *think* you have self control) .