Grapefruit Curd is a delightfully bright, tangy twist on the usual citrus curd. Serve it with pound cake or serve a spoonful with yogurt and granola for a decadent breakfast.
Add enough water to a medium saucepan to come about 1-inch up the side. Bring to a simmer over medium-high heat.
Meanwhile, find a bowl just large enough to fit inside the saucepan without touching the top of the water. A metal bowl is preferred, but a glass bowl will work just fine.
Whisk the egg yolks and the sugar together in the bowl until smooth and light yellow, about 1 minute. Add the grapefruit juice and the zest and whisk until smooth and combined.
Once the water reaches a simmer, reduce the heat to maintain at a gentle simmer; place the bowl with the egg mixture on top. Whisk continuously until the mixture is thickened, about 8 minutes in a metal bowl or closer to 12 or 13 with a glass bowl. The thickened mixture should be light in color and coat the back of a spoon (curd will thicken more as it cools).
Remove from the heat and whisk in the butter, one piece at a time, allowing each pieces to melt before adding more.
Pour into a clean container; place a layer of plastic wrap directly on the surface of the grapefruit curd, and then cover. Store in the refrigerator for up to two weeks.
Notes
Even if you use the juice and zest of ruby red grapefruit, the curd will be a barely darker than a lemon curd, rather than pink, due to the egg and butter in the recipe. If you wish for your grapefruit curd to be pink, you can add a drop of food coloring after adding the butter.Makes about 1 pint (2 cups).