See Notes below before you start.
Thinly slice the apple quarters (from top to bottom).
Place in a preserving pan (or similar) with cranberries, orange juice, orange zest and mixed spice.
Cover the pan with a tight-fitting lid and gently simmer for about 10 minutes or until apple is softened and cranberries have all popped.
Lower the heat, add the sugar and stir until dissolved, whilst breaking up the apple with the back of a wooden spoon.
Bring the pan to a rolling boil on a high heat, stirring continuously and set a timer for 5 minutes (or boil until 104°C or 219°F is reached on a digital or jam thermometer). Then remove from the heat.
Test for set by pouring a few drops of jam onto a chilled saucer, then put in fridge for 30 seconds.
Push a finger through the jam which should no longer be watery and form a gel like crinkle. (Harder to see in this jam as it’s so fruity but you’ll know if it’s standing upright on the plate).
Pot up immediately into hot jars (using a ladle and jam funnel if you have one) and screw or clip on lids whilst jam is still hot.
Jam is ready to serve once cool.
Store in a cool, dry, dark place and once open in the fridge (use within a few months). For best quality and colour eat within 12 months but will be safe to eat for years.