I adapted the recipe from one of my favourite cooking sites, the Gluten Free Scallywag. I was amazed how quick and easy it was. The last time I attempted a lemon butter, it seemed like hours of stirring, only to find the egg cooked when I added it to the mixture, causing great big lumps of solid egg-white throughout the mix. This version has the egg and sugar added from the start so there is no chance of that happening.
Here is my version of the recipe:
Lemon Butter (Lemon Curd)
2 egg yolks
100g castor sugar
50ml lemon juice (1-2 lemons)
3tsp lemon zest (about three lemons)
100g cold butter, cut into 1cm cubes
Beat together eggs, egg yolks and sugar until light and fluffy.
Measure out lemon juice and zest and keep aside.
Heat egg and sugar mixture on low to medium heat, stirring briskly until sugar has disolved. A heavy based saucepan works best. Add lemon juice and zest, and continue stirring.
Gradually add the butter, one cube at a time, adding another when the last has disolved. While this is happening the mixture will begin thickening.
Once all the butter has disolved reduce the temperature to a low heat and stir gently as it reaches a boil. This should take 3-4 minutes, and the mixture should now be nice and thick.
Remove from the heat and press through a sieve to remove the lemon zest. You can ignore this stage if you want a chunkier curd. Pour into a sterilised* jar and refrigerate for 3-4 hours until firm.
* To sterilise a jar, slowly heat in a cool oven for 20 - 25 mins, or follow these instructions.