A delicious, light and fresh dessert, with a meringue base and a light lemon curd topping. Garnished with fresh lemon slices, blueberries, mint leaves and powdered sugar.
Using an electric mixer and a clean, narrow, deep bowl or the bowl of a stand mixer fitted with the whipping attachment, beat egg whites and cream of tartar (or salt) on the highest setting until soft peaks form (using a narrow deep bowl ensures the beaters are well into the whites and will build up the greatest volume). Add sugar, 1 tablespoon at a time, without stopping the mixer, beating constantly until thick and glossy. Add 3 tsp of cornstarch with the last tablespoon of sugar. Whip mixture until sugar is completely dissolved. Dissolving the sugar should take about 10-12 mins (or if using normal granulated sugar, about 15 mins.) Test the mixture by feeling a small amount of the meringue between two fingers if it is grainy beat longer. Once the sugar is dissolved, use a rubber spatula to fold through vanilla and vinegar in a few, quick strokes.
Spoon meringue into the springform cake ring and shape the uncooked meringue using the springform cake tin as a guide into one giant meringue. Make a slight indentation in the top, pushing the extra meringue towards the edges. You want it just slightly dished. This is where your lemon curd will go, so you want the edges higher, so it stays put in the middle. Carefully lift the springform cake pan ring straight up and remove. Place the uncooked meringue cake into the oven.
To serve: (Put curd on meringue just before serving) Spoon cooled lemon curd on top of meringue and spread evenly in the indentation, leaving the outermost edges uncovered. Arrange some lemon slices around one side. Top with a scattering of fresh blueberries and some fresh mint leaves. Dust with powdered sugar, if desired. Would also be nice with a dollop of whipped cream.