Place chopped quince in a medium saucepan and cover with cold water,bring to boil and cook until quinces are soft.

Drain cooked quince and puree while warm to a smooth pulp.

Scrape warm quince puree into a heatproof bowl,and rest bowl on a saucepan of simmering water. Make sure the bowl does not touch the water.

As the puree heats,whisk together eggs,sugar,salt and lemon juice in a separate bowl.

Add egg mixture to puree in the double boiler and cook the mixture for about 20 minutes,or until it has thickened. Stir occasionally and do not overheat;overheated eggs could cause the curd to curdle.

Once cooked,cool slightly then add the cold butter and mix until butter dissolves and curd takes on a shiny gloss.

Let cool completely,then store in a clean jar in the fridge for up to two weeks.

Frank's tip:To stop quinces from discolouring,keep them in water with a squeeze of lemon.