Citrus Fruit Spread

Pour enough hot water to come 5 cm|2" up the sides of the inside of the slow cooker.

Combine the lemon juice, sugar, and butter in a heatproof bowl that will sit inside the slow cooker. Sit the bowl in the slow cooker and pour enough water to come halfway up the sides of the bowl.

Turn the setting on the slow cooker to high and leave the bowl to sit in the water, stirring occasionally, until the sugar, butter and lemon juice have dissolved together; 15 minutes.

Remove the bowl from the slow cooker, leave to cool slightly, and set the slow cooker to low.

Strain the beaten egg into the heatproof bowl and whisk until well combined.

Return the bowl to the slow cooker and cover with a lid. Cook on the low setting for 1 hour 30 minutes - 2 hours until thickened, stirring from time to time.