Cinnamon Hot Chocolate Tart

I seem to be on a bit of a Mexican flavouring kick recently. Not that I'm complaining! Spicy, rich, complex flavours are just fine by me. This makes such a lovely, smooth filling, with just a suggestion of chilli heat. And I like distinct foods that complement each other when eaten together, which is why I put the cinnamon in the crust.
NOTE: try replacing the heavy cream with crème fraîche; it makes for an almost mousse-like consistency.

Crust
1 cup (4oz/120g) flour
¼ tsp salt
1 Tbsp sugar
¾ tsp cinnamon
½ cup (4oz/114gr) butter, cut into pieces
½ tsp vanilla
2 Tbsps + cold water

NOTE: The pastry needs time to cool in the refrigerator not once, but twice, for about 15 minutes each time, and then another 15 minutes to pre-bake in the oven, a total of about 45 minutes.

1. Put the flour, salt, and sugar in a large bowl. Add the butter pieces and pinch with your fingers to create a crumb texture (it's like playing in sand).
2. Make a well in the middle, and pour in the vanilla and water. Quickly work in the flour to create dough. Do not over-mix. 
3. Pat into a thick disk, wrap in plastic, and refrigerate 15 minutes.
4. Roll out the dough, line the tart shell, and chill another 15 minutes.
5. Pre-heat the oven to 400°F.
6. Put baking weights in the shell and bake for about 15 minutes or until the crust is ever-so-lightly browned.

Filling
6 oz (170g) 70% chocolate, chopped fine
1 cup heavy cream
½ cup milk
1 tsp vanilla
¼ cup sugar
⅛ tsp cayenne
3 egg yolks

1. Heat the oven to 325°F.
2. Bring the cream and milk to a very slow boil in a saucepan.
3. Remove from the heat and add the vanilla and the chopped chocolate, stirring to melt the chocolate completely.
4. In a bowl, whisk together the yolk, sugar and cayenne until yolk turns a pale yellow.
5. Very slowly whisk in the chocolate mixture into the egg mixture. Do this slowly; this is to gradually increase the temperature of the egg and avoid making scrambled eggs with the hot liquid.
6. Strain the mixture into the baked tart shell.
7. Bake about 35 to 40 minutes or until set. The pie will puff up a bit when it is cooked, and will settle again as it cools.
8. Let it cool completely, which can take a few hours.
9. Only once it is completely cooled, dust with cocoa powder. If you dust it before this, the surface will still be hot and damp and the powder will just get wet.
10. Delicious accompanied by a fresh sprig of currants or other tart fruit.