Wash and Dry the Lemons: Rinse the lemons under running water and wipe them with a paper towel to remove any dirt or wax from the skin.
Grate the Zest and Squeeze the Juice: Use a fine grater or zester to grate the yellow part of the skin of the lemons, avoiding the white pith. Cut all lemons in half and squeeze out the juice.
Prepare the Lemon Mixture: Whisk the eggs together in a pot. Then stir the remaining ingredients (caster sugar, lemon juice, zest and butter) and place the pot over medium heat.
Cook Until Thickened: Continuously whisk the mixture over the heat until it coats the back of a spoon and slightly thickens—this might take around 7-10 minutes. Be cautious not to let the mixture come to a boil, as it may risk splitting.
Strain and Jar the Lemon Curd: Remove the saucepan from the heat and allow the mixture to cool. Pour the lemon curd into a sterilized jar (or two small jars) through a fine mesh sieve, seal them tightly, and let the curd continue to thicken.
Chill: Store the freshly made lemon curd in the refrigerator for at least 6 hours until set. The curd can be refrigerated for up to a month. Remember, once the jar is opened, consume the lemon curd within a week.
Enjoy your homemade Mary Berry lemon curd!