Make sure you have your butter weighed out and ready (if your kitchen is warm, put it in the fridge to keep cold)
Add the lemon juice, lemon zest, caster sugar, eggs and egg yolks to a pan or pot. Whisk everything together
Place the pan on the hob/stove on a low heat. As the mixture heats, stir it gently but continuously. It will take around 5-8 minutes to thicken, but the time depends on your hob and the heat level so don't worry if it takes a little longer
To test that it's thick enough dip a wooden spoon into the mixture. Then run a line with your finger through the liquid on the spoon (please be careful as the liquid will be hot!). If the line stays then you can take the pan off the heat. If the other liquid on the spoon drips into the line, you need to heat the mixture for longer
When it's ready, remove it from the heat and add the butter straight away, stir the mixture until the butter melts and combines
Pour the lemon curd into a bowl (you can sieve it into the bowl using a fine sieve if preferred or necessary) and cover with cling film so that the cling film directly touches the top of the curd, put it in the fridge to cool down fully
Store in an airtight container in the fridge for 1-2 weeks, or in the freezer for up to 3 months
Video
Notes
Fresh lemon juice is an absolute must for this recipe. You just won't get the same flavour from bottled lemon juice.
This recipe uses caster sugar, but you can use granulated sugar too. Just don't use golden caster sugar, or any type of brown sugar to make lemon curd, as this will affect the flavour and colour of it.
I use a mix of whole eggs and yolks in this recipe. This balances out the richness of the egg yolks and also gives the curd a beautiful texture.
I recommend using unsalted butter to make lemon curd, it's also better to use cold butter as it helps the lemon curd cool down and thicken faster.
Although I provide cup measurements, I highly recommend weighing your ingredients out using digital kitchen scales. It is the most accurate way to measure ingredients and will ensure the best results. Digital scales are very low cost and can be purchased for around £12 ($16.50).
For teaspoon (tsp) and tablespoon (tbsp) measurements, please use measuring spoons and not the type of spoons you eat with. Again this will ensure accuracy and provide the best results.