- With the rack in the middle position, preheat the oven to 200°F (95°C). Line a baking sheet with parchment paper.
- In a bowl set over a pot of simmering water, heat the sugar and egg whites, whisking constantly, until the sugar has dissolved. Remove the bowl from the heat.
- Whisk the egg white mixture with an electric mixer until it has cooled completely and stiff peaks form (a stand mixer is very handy for this step). Whisk in the cocoa powder.
- Transfer the meringue to a pastry bag fitted with a plain tip. Pipe small meringues directly onto the prepared baking sheet.
- Bake for 2 hours or until the meringues have dried out and easily detach from the parchment paper. Turn off the oven and continue drying the meringues for 2 hours, keeping the oven door slightly ajar with a wooden spoon. Remove from the oven and let cool completely on the baking sheet. The meringues will keep for 3 weeks in an airtight container at room temperature (see note).
- In a bowl, combine the flour, cocoa powder and salt.
- In another bowl, cream the butter and sugar with an electric mixer. Add the egg yolks one at a time and mix until smooth.
- With the mixer running at low speed, or using a wooden spoon, add the dry ingredients and mix until smooth. Press the crust firmly into an even layer along the bottom and up the sides of a 9-inch (23 cm) round, 1 inch (2.5 cm) high tart pan with removeable bottom. Using a fork, prick the bottom of the crust all over. Refrigerate for 30 minutes.
- With the rack in the middle position, preheat the oven to 400°F (200°C).
- Cover the crust with a sheet of parchment paper and fill with dry beans (or ceramic pie weights). Bake for 18 minutes. Remove the peas and the parchment paper. Bake for another 2 minutes to dry out the crust. Let cool completely on a wire rack. Reduce the oven temperature to 250°F (120°C).
Caramelized White Chocolate Cream
- Place the chocolate on a non-stick or silicone mat-lined baking sheet.
- Bake for 40 minutes, stirring the chocolate with a spatula every 10 minutes, until it turns the colour of caramel. Transfer the chocolate to a bowl.
- Place the tart pan on a baking sheet. Set aside.
- In a small bowl, sprinkle the gelatin over the water. Let bloom for 5 minutes.
- In a pot, bring the cream to a boil over medium heat. Remove from the heat. Pour over the caramelized chocolate. Add the gelatin and whisk until completely dissolved. Strain the white chocolate mixture through a sieve directly into the crust. Refrigerate for 3 hours or until the cream has completely set.
- Line a baking sheet with a silicone mat or parchment paper.
- In a small non-stick skillet over medium heat, cook the honey for 1 to 2 minutes. Add the buckwheat and mix with a wooden spoon to coat each grain in the honey. Spread the buckwheat out on the prepared baking sheet. Let cool completely. The caramelized buckwheat will keep for 1 week in an airtight container at room temperature.
- Using a lemon zester, remove long, thin strips of zest from the clementines. Set aside.
- On a work surface, supreme the clementines by removing the skin, pith and membrane with a knife and divide into skinless sections. Compost the skin.
- When ready to serve, garnish the tart with meringues, caramelized buckwheat, clementine zest and supremes.
Although the long waiting times for each component of this recipe make it appear complicated, many of the steps can be prepared in advance, such as the meringues, buckwheat and even the crust.
The meringues make a great gift.