In a medium sized metal bowl, whisk together the 3 eggs, the sugar, the lemon juice until thoroughly combined. Begin setting up for the next step, by bringing water in a medium sized saucepan to a simmer. Make sure the saucepan is big enough to hold the bowl.
On medium heat, place the bowl of mixture into the the simmering water. Do not pour the contents in :) Continuing whisking the mixture until it starts to thicken. It should resemble thicker salad dressing or hollandaise sauce. If you are technical, a candy thermometer should read at 160 to 170 degrees Fahrenheit. The entire cooking process should take around 10 t 15 minutes.
Be patient! :)
Once the mixture has finished cooking, take the bowl off the heat. Whisk in the butter until melted along with the lemon zest. Cover the lemon curd and refrigerate. It should last about a week and a half.
I hope you try out this recipe. It is truly delicious and versatile recipe to make. Maybe lemon curd will appear next to your strawberry preserves soon :)