Melt chocolate either in the microwave or in a glass bowl over a pot of water (make sure the water does not touch the bottom of the bowl) on low heat. Set aside to cool to warm.In a medium pot, heat over low the milk and cream, do not boil. Remove from heat and let cool to warm.
In a medium pot add yolks and sugar, whisk together until combined, then add flour and vanilla, place pot over low heat, add warm milk/cream, whisking continuously (don't stop) until thickened, remove to a glass bowl and whisk in melted cooled chocolate until combined. Cover with plastic wrap (make sure wrap touches the cream mixture) and refrigerate at least 2-3 hours. Depending how long you leave the cream in the fridge you may want to whip it for about 30 seconds to get it nice and creamy again.
FOR THE PIE DOUGH
In a large bowl, mixing bowl or food processor bowl add the flour, salt, baking powder, sugar and sifted cocoa (it can be sifted directly into the bowl), mix together with a whisk. Add the egg, yolk and butter, combine with the flat beater, pulsing or with a fork or clean hands until almost combined.
Move to a lightly floured flat surface and gently knead a couple of times just to bring it together. Wrap the dough in plastic and refrigerate 30-60 minutes.
PUTTING IT ALL TOGETHER
Line an 8 inch / 20cm round cake pan with parchment paper or grease and flour or spray and 8 inch / 20cm springform pan.
Divide the dough in two (one a little more than the other). Roll out the larger part to a bit thicker then ⅛" thick circle, place the dough in the prepared pan and up the sides, trim around the edges. Spread the cream filling evenly on the dough.
roll out the remaining dough and place on top of the filling and seal the edges. Brush the dough with milk and sprinkle with the almond flakes. Cover and refrigerate for 30 minutes.
Pre-heat oven to 350F/180C.
Bake for approximately 35-45 minutes. Let cool at room temperature in the pan, then cover the pan and refrigerate for at least 2 hours. Transfer the cake to a clean plate, dust with powdered/icing sugar and serve. Enjoy!
Notes
Store the baked cake covered in the refrigerator for up to 3 days. Since it is filled with pastry cream, I like to serve it chilled or let it sit out for a few minutes before slicing.The chocolate shortcut pastry can also be made ahead and frozen. Wrap the dough well in plastic wrap and freeze for up to 1 month, then thaw it in the refrigerator before using.If you find the dough too dry add a bit more butter or a tablespoon or two of milk, too wet add a bit more flour, a tablespoon at a time.