Dough: Put all the ingredients one by one in the food processor in the above order, on the lowest setting, and mix very briefly, just enough to let everything stick together nicely.
Form a ball, wrap the dough in cling film, and let it chill in the refrigerator for at least half an hour. Meanwhile, make the flan filling.
Filling: Cut the vanilla pod lengthwise and scrape out the seeds with a knife. Mix it well with the sugar until the speckles are spread out. Boil the vanilla pod with the milk.
Beat the vanilla seeds together with the eggs and coconut blossom sugar until a nice creamy mass.
Remove the vanilla pod from the milk. Pour the warm milk over the creamy mixture and stir well together until a white and airy batter forms.
Grease the baking pan with a layer of flour.
Roll out the dough between two sheets of baking paper with a bit of flour, to 2 to 3mm.
Remove the top baking paper and flip into the pan. Remove the second baking paper. Press the dough nicely into the baking pan, prick some holes in the bottom with a fork, and roll the edges with the rolling pin.
Bake the dough for 25 min at 190°C blind with baking paper and baking pearls or dry beans.
Remove the pearls and the baking paper, let it cool for a bit but do not turn off the oven.
Place your pre-baked tart base in the oven, pour the filling into a jug or mixing cup with a spout and fill the tart in the oven: this way you can fill it nicely to the top without spilling.
Bake the filled base with the flan mixture for 18 to 20 min at 180°, depending on how high your tart is.
Let it cool completely.
Whip cream and sugar together until it is still creamy.
Let the sugar melt in a non-stick pan without stirring until all the sugar is melted. Add the warm pistachios to the melted sugar. Mix the nuts well with the sugar. Let the caramelized nuts cool on a stone or a sheet of baking paper. Chop the nuts coarsely.
Spread a thick layer of whipped cream over the tart and finish with the caramelized nuts.