Wash the apples, core them and cut them in a smaller pieces (you can leave the skin on). You should have 500 grams (1/2 kg or 1 pound) of apple chunks, once they are ready.

Put the apples with water or lemon juice (if using) to a small saucepan and leave on a low heat to simmer and soften. You can also do this in a microwave for about 5-6 minutes. Stir as necessary to prevent the apples catching on the bottom of the pan (or stir the apples in the microwave every minute or so to make sur the heat is evenly distributed).

Once the apples are soft, push them through a fine mesh sieve to get rid of the apple peel and place to a glass bowl (or other heat proof bowl, but not stainless steal or metal). Make sure you get all the apple pulp and juice an only discard the apple peel.

Add about 1 inch or 2 cm of water to another medium size saucepan and bring to gentle simmer over a low to medium heat on your hob.

Add the butter. sugar, lemon juice (if not already in) with a good pinch of salt to the apple mixture.

Place the bowl over the saucepan and let the sugar dissolve first. Stir gently to make sure all ingredients are incorporated and the sugar has dissolved properly (check on the back of a clean spoon for any sugar crystals).

In the meanwhile, beat the eggs together (using either 2 whole eggs or 4 egg yolks - if you have a leftover from another recipe or you have a plan for the egg whites later).

Strain the eggs through a fine mesh sieve to get rid of any impurities.

Once the sugar has dissolved, slowly add the eggs to the main apple mixture.

Carry on stirring the apple curd mixture, ensuring that the heat is very low and that the water doesn't boil (only simmers).

Stir gently for another 20 minutes or until the mixture thickens and becomes lovely and creamy.

Taste and add more lemon juice, cinnamon or other spices to get your desired flavour.

To achieve a smooth apple curd, pour and press the hot mixture through a fine sieve again.

Pour carefully into prepared glasses or other suitable containers.

Keep in a refrigerator and use within 2-3 weeks.