Roll out the shortcrust pastry using a rolling pin and, after obtaining a sheet, use it to line a buttered, circular oven-dish. Trim off the dough that comes over the rim of the receptacle and prick the base with the tongs of a fork.
Cover with a sheet of parchment paper and fill with dry beans so that the crust doesn’t bubble during cooking. Bake in a preheated oven at 350°F for 10-12 minutes. When done, remove from the oven and remove the beans and parchment paper. Let cool.
Wash the blueberries for 15-20 seconds and drain. Place a small pot with the wine and 1 tbsp sugar on the stove. Stir and as soon as it begins to boil, add the blueberries. Put the gelatin in hot water and leave to soften for a couple of minutes.
In the meanwhile, whisk together the ricotta with the remaining sugar and vanillin. Once creamy, add the whipped cream and stir carefully. Add the blueberries and gelatin, well wrung out.
Mix everything together carefully and use it to fill the tart crust.
Put the tart into the fridge to chill for a couple of hours. Serve cold sprinkled with almond slivers.