Step 1

Grab a medium heatproof bowl and squeeze the lemons, zest the skin, add the natvia (or erythritol) and add the butter. Set the bowl over a pan of gently simmering water. Don't let the bowl touch the bottom of the pan. Stir the mixture until all the butter has melted.

Step 2

Lightly whisk the eggs and egg yolk, then stir into the heated mixture. Stir and cook for around 10 mins until the mixture coats the back of a spoon.

Step 3

Remove from the heat and put the mixture into sterilised jars and store in the fridge for up to 2 weeks.