Lemon Butter

Modern (with long history). Gluten Free.

I modified this recipe from Julie Goodwin's lemon butter recipe
Ingredients

• 4 eggs
• 1 cup of sugar
• 125 grams of unsalted butter at room temperature (not melted)
• very fine zest of 2-3 lemons
• ½ cup lemon juice (about 2-3 lemons)

Method

• Prepare two small glass jars by putting them on a tray and pouring boiling water over them and the lids. Dry in the oven on 120 degrees Celsius for 10 minutes. 
• Crack eggs into a medium sized Pyrex/heat proof glass bowl and beat them well.
• Add sugar and beat into the eggs until combined.
• Put bowl over a simmering (medium to low heat) pot of water and beat in the lemon, butter and zest. 
• Put on a timer for 20 minutes. Keep beating for 20 minutes (you can use an electric whisk on low) it will thicken.
• Using a confectionery thermometer, make sure the mixture just exceeds 70 degrees Celsius to kill any potentially harmful bacteria in the eggs. Do not go above 75 degrees Celsius. 
• Pour warm mixture into the jars. Place the lids on firmly. Gently tip the jars upside down so that the heat of the mixture kills any potential bacteria left in the jars. Store upright jars in the fridge. 

You can find some basic history about lemon curd located at British Food: A History.