You will ideally need a balloon whisk and either a saucepan with a thick base or a Pyrex bowl heated from below by a water bath; the important principle is that the mixture is ‘cooked’ gently while it is continually stirred and mixed. If you apply too much heat too quickly, you’ll end up with lemon flavoured scrambled eggs…
Always prepare the ingredients first - there is no time to do this while cooking. For cautious cooks or first time lemon curd makers, the water bath method is safer, as long as the hot water isn’t boiling vigourously (about 85-95 degrees C should be OK) and it mustn’t actually touch the bottom of the bowl - it’s the steam that does the cooking. In my experience, a thick bottomed saucepan on a gas ring at its absolute lowest setting is fine, BUT you must continually stir and whisk.
This makes three large jars plus a bit - approx. 1800g of a sharpish lemon curd. It’s as simple to make a large amount as small, but you can easily divide the recipe quantities in two.
6 medium eggs
6 medium eggs (yolks only)
8 Lemons (unwaxed) approx - 325g juice. You may need a few more, depending on size.
400g unsalted butter
450g white caster sugar - 50-100g more if you like a sweeter version
Gently melt the butter - take off the heat as soon as it has melted. Whisk the eggs and yolks together in a bowl. Zest and squeeze the lemons, adding the juice and zest to the melted butter. Return to the heat and add the sugar - stir until dissolved. With the heat at the lowest possible, add the eggs, whisking continuously. Now, continue whisking as the gentle heat cooks the mixture - this is likely to take about 15 - 20 minutes or so. You will eventually notice a thickening of the mixture - it should coat the back of a spoon without dripping off. Remove from the heat and whisk a little longer. Fill clean, warm jars (10mins in the oven at 100C) and fit the lids immediately. Tighten the lids as they cool.
Keeps for about 1 month in the fridge - do not keep at room temperature. Dangerously addictive, I’m afraid.