Set up an ice water bath with a sieve in a bowl, set over a larger bowl full of ice and water.
Set up a double boiler: Take a heat-proof bowl and set it over a saucepan filled with approximately 2 inches of water so that the bottom of the bowl does not touch the water. Remove the top bowl and bring the water to a boil.
Place all the ingredients into the bowl and place the bowl over the boiling water, whisking constantly, until the mixture almost comes to a boil and thickens. This should take approximately 10-15 minutes.
Immediately pour the mixture into the sieve, and use a rubber spatula to lightly push down so that the curd separates from any solids.
When the mixture cools, remove from the ice water bath, and place a piece of plastic wrap directly on the curd. Refrigerate for approximately 2 hours or until cold and thickened.