1/2cupfresh lemon juiceMeyer lemons are especially wonderful, if you have them
4tablespoonsunsalted buttercut into small cubes
In a small saucepan, combine the blueberries and lemon juice, cover, and place over medium heat. Cook until the blueberries pop and the liquid bubbles, about 5 minutes. Pass the blueberries through a strainer, pressing well with a spoon. Be sure to scrape all the brilliant purple puree on the underside of the strainer into the bowl to use. Pour the blueberry puree back into the saucepan and set aside to cool.
Whisk together the egg yolks and egg until combined. While whisking, pour in sugar and whisk until a light yellow color. Add the egg mixture to the blueberry puree in the sauce pan, and continue whisking until creamy and well incorporated, about one minute. Place over medium heat, whisking constantly, until the custard thickens and can coat the back of a wooden spoon, about 8-10 minutes. Remove the pan from the heat, and stir in the butter, one cube at a time.
Strain into a bowl or jars, cover the surface with plastic wrap, and chill in the refrigerator for at least one hour.
Many people ask if blueberry lemon curd can be processed in a hot water bath for long-term storage, similar to jams and jellies. I know friends who do make and can fruit curds. In general, what I have learned is frozen lemon curd can be kept much longer (up to 1 year) than lemon curd that is preserved by canning (3-4 months), but the key in doing it the latter way is using bottled versus fresh lemon juice. The worry is that fresh lemon juice lacks the acidity to make the canning safe.I recommend checking out these two links that have info/recipes for canning lemon curd:http://www.uga.edu/nchfp/how/can_02/lemon_curd.html http://www.uga.edu/nchfp/publications/nchfp/factsheet