Method

​1 Preheat the oven to 170°C/fan 150°C/gas mark 3.

2 Peel and slice your cooking apples and place in a deep ovenproof dish measuring 24 cm (9.5 inches) along with the blackberries. Sprinkle over the sugar. Microwave for 3 minutes to help soften the fruit.

3 For the sponge: cream the butter/margarine and the caster sugar together until pale. Use an electric hand mixer if you have one. Beat in the eggs. Stir the gluten-free flour until it’s all combined.

4 Spread the sponge mixture over the fruit. Bake for 50 minutes in a pre-heated oven.

5 Once baked remove from the oven. Whisk the egg whites using an electric hand whisk on full speed until stiff peaks form when the whisk is removed. Add the sugar in gradually, still whisking on maximum speed until the mixture is stiff and shiny. Spoon the meringue mixture over the sponge.

6 To achieve swirls - go around the edge of the meringue, using a cork screw making a spiral movement at regular intervals.

7 Turn the oven up to 180°C/fan 160°C/gas mark 4 and bake for 10 minutes. Serve warm either with custard or cream.