Mix all the ingredients to make the short crust pastry. Work the dough well out and smooth and let it stand for at least 1 hour in a cold room.
Take a Tarte form and place it on a baking paper. Draw around the form on the paper with a pencil and cut it out. This is your tart liner.
Preheat oven to 350 Fahrenheit/ 180 Celsius.
Butter the Tart form and dust it well with flour. That will prevent the dough to stick on the form while baking.
Take out your dough and roll it out to approximately ½ cm thickness. Turn the baking form and place it on the dough. Calculate 2 cm more from the form and cut out all around. 2 cm more are required or your dough will be too short to fit into the baking form.
Place the cut out dough into the buttered form.
Poke with a fork a few fine wholes into it. Add the previously cut out baking paper on top with some weight such as a handful of beans or lentils. That will prevent the dough to blow up in the center and to stay even. Bake the dough by itself for 15 mins at 350 Fahrenheit/ 180 Celsius.
For the Frangipane filling
In the meanwhile prepare the filling.
In a bowl mix Butter, sugar smooth.
Add the Almond flour, flour and Eggs. Mix it all well so that no lumps are left.
Build the tart
Once the dough is finished baked, take it out and remove the baking paper with the beans/lentils. Fill into the short crust pastry the almond paste mix.
You can choose to use canned or fresh mirabelle plums. Arrange the preserved mirabelles on top.
Bake the Tart for about 1 hour at 350 Fahrenheit/ 180 Celsius.
Notes
We leave the core in the Mirabelle (kind of gives an extra flavor). Feel free to remove them if you prefer without!