Place the granulated sugar in a jug and add boiling water to double the volume. Add the lemon juice and stir until the sugar has dissolved. Leave to cool.
Cut up any large strawberries and place with all the other berries in a jug. Pour over the cooled syrup and leave to marinade for at least 2 hours (or preferably overnight).
Line 2 baking sheets with greaseproof paper and draw 3 x 12cm circles on each tray.
Whisk the egg whites and cream of tartar until soft peaks form, then slowly whisk in the caster sugar, 1tbsp at a time. Whisk until thick and glossy then stir in the coconut gently.
Spoon the meringue evenly onto the traced circles.
Bake in the oven at 100°C / 210°F / Gas Mark ¼ for 1½ hours or until crisp. Then cool on trays.
