1. Peel core and chop the apples into small pieces.

2. Combine them with 250ml/1 cup water in a large saucepan and bring to a boil over high heat 220°C/425°F.

3. Reduce the heat to medium-low 140°C/285°F and let it simmer until the apples are soft about 20-25 minutes.

4. Strain the apple mixture through a cheesecloth or a fine-mesh sieve into a large bowl pressing on the solids to extract as much juice as possible.

5. Discard the solids.

6. Measure the apple juice and add an equal amount of sugar.

7. If using add 1-2 tablespoons lemon juice or ascorbic acid to prevent discoloration.

8. Bring the apple juice and sugar mixture to a boil in a large saucepan over high heat 220°C/425°F stirring occasionally.

9. Reduce the heat to medium-low 140°C/285°F and let it simmer for 10-15 minutes or until the marmalade has thickened and passed the "wrinkle test".

10. Remove the saucepan from the heat and stir in 1 teaspoon sodium benzoate.

11. Let the marmalade cool slightly before transferring it to a clean glass jar or airtight container.

12. Store the marmalade in the refrigerator at 5°C/40°F for up to 6 months or in the freezer at -18°C/0°F for up to 1 year.