• Adjust oven rack to middle position and preheat the oven to 160°C
• Crumb the gluten-free biscuits in a food processor or in a plastic bag with a rolling pin.
• Toss with the melted butter and lemon zest.
• Spray a 22 cm x 4 cm deep pie dish with a non-stick cooking spray.
• Shake the crumbs level in the dish and then work some up the sides of the dish with the back of a tablespoon.
• Wipe the edge of the dish to remove loose crumbs.

To make the filling

• Decant the lemon curd out of the bag into a medium-size mixing bowl.
• Separate the eggs. The whites go into another spotlessly clean, medium-size glass (not plastic!) mixing bowl.
• The yolks are added to the lemon curd.
• Mix the yolks into the lemon curd with a wire whisk. Decant the lemon curd mixture into the crumb lined pie dish.

To make the meringue

• Beat the egg whites with the electric beater on high speed. Beat until the whites stand up in soft peaks. Do not add castor sugar until this stage.
• Now add the castor sugar mixture (in the small foil packet) little by little while beating on high speed. You will end up with a snow-white, thick and shiny meringue. Use two tablespoons to scoop and blob the meringue all over the curd filling.
• Start in the middle, no need to take it right up to the edges, I think I went too far with mine.
• Bake for 30 minutes. Then switch off the oven. Do not open the door but leave the pie standing in the warm oven for 30 – 45 minutes to firm and dry out the meringue.
• Remove from the oven and leave to cool down.
• Store in the fridge for a good few hours to allow the curd to set before cutting.
• Stored in the fridge in an airtight container, it will keep for 3 – 4 days.