n n Prepare and bake your tart dough. n n Wash the wild berries under a running water and drain them well. In a bowl mix together 20g / 0.7 oz of sugar, freshly grated lemon zest and freshly squeezed juice of ½ lemon. Add 100g / 3.5 oz of blueberries and give it a good toss. Set aside until needed.n n In a mixing bowl whip together mascarpone, greek yogurt, vanilla beans and rum until you get a soft, light and shinny texture. In another smaller bowl whip the whipping cream with 40g / 1.4 oz of sugar until you get a soft peak. You should not whip too much. Add 1/3 of the whipping cream to the mixing bowl where you have your mascarpone - yogurt mixture and combine well, using a spatula. Gently fold the rest of the whipping cream, so that you get a light and airy cream.n n Gently pour 2/3 of the cream onto the bottom of the prebaked tart crust, and spread evenly using a flexible spatula. Add sugar coated blueberries (from step 1) to the remaining 1/3 of the cream and combine well, to release the juice and flavour from the berries. Spread the blueberry cream over the top of the tart. Arrange the blueberries to your liking, we like to completely cover the tart filling. Refrigerate for 1 hour and serve. You can sprinkle with some icing sugar if you like.nnn  n