Step 1

Finely chop your chocolate, and cut your butter into several smaller pieces.

Step 2

In a saucepan, bring the cream and 1/4 teaspoon of the ground nutmeg just to a boil around the edges. Remove it from the heat and immediately dump in the chocolate and the butter. Let it sit undisturbed for a minute. Then gently, starting from the center of the pot and stirring in small circles, begin to stir the melted chocolate into the cream. Stir in progressively larger circles (but still gently because you don’t want extra air to get in there and ruin the silky consistency), until it is completely mixed and is a uniform color.

Step 3

Set aside and allow to cool for just a bit, around 10 minutes, then taste and add up to another 1/4 teaspoon of nutmeg to get a nice spicy flavor in the chocolate. Next, pour the chocolate mixture into the pre-baked tart crust. Set it in the fridge and let it chill for a couple of hours before serving.

Step 4

Serve chilled in thin slices with soft pillows of whipped cream mounded on top.

Step 5

In a food processor, grind the hazelnuts and the flour together until you have a pretty fine powder. Transfer this to a small bowl and whisk in the baking powder and salt.

Step 6

In a stand mixer, using the paddle attachment, beat the butter at medium speed for a minute. Then, beat in the sugar on medium-high speed until the butter and sugar are light and fluffy and fully creamed together, about 6 minutes. Stop on occasion during this process to scrape down the sides.

Step 7

Beat in the egg yolk until fully incorporated, a couple minutes.

Step 8

Use a spatula to fold the dry ingredients into the wet. Then, mix it with the mixer on slow speed for a couple of minutes, until completely combined. Stop and scrape down the edges now and then to make sure everything gets mixed in. Gather the dough into a ball and pat it into a thick disc, then wrap it in plastic wrap and chill in the fridge for at least 2 hours or up to 24.

Step 9

On a lightly floured surface, roll out the crust and carefully transfer it to a 9-inch tart pan. Press it into the tart pan, using your fingers to press together and fix any cracks (my dough cracked quite a bit, but it was really malleable and easy to press back together, making it quite nice to work with). Freeze the tart shell for 30 minutes.

Step 10

Preheat your oven to 350° F. Line the frozen tart shell with parchment paper or aluminum foil and fill it with dry beans or pie weights. Put it in the oven and bake for 30 minutes. Take it out of the oven, remove the weights and lining, then pop it back into the oven to bake for another 10 to 15 minutes, until golden brown.

Step 11

Transfer to a cooling rack, and allow to cool before filling with the chocolate filling.