Start this recipe with the sweet pastry base. Make a pastry using the rubbing in method and bind with water. Use to line a 9inch fluted flan tin and bake blind in the oven at 200°C for 20-25 minutes until completely cooked through. Next, make the citrus filling by mixing together all the ingredients in a saucepan and bring to the boil until thick and glossy. Pour into the pastry base and allow to set completely for 1 hour. When ready, tip the juice from the chickpeas into a mixer fitted with a whisk and whip to stiff peaks. Add in the cream of tartar, followed by the icing sugar and continue whisking till you have a glossy meringue. Pipe over the set citrus filling and blow torch or place under a hot grill to brown.