In a mixing bowl, beat egg yolks with granulated sugar for about 3 minutes until they turn pale and creamy. Meanwhile, heat ¼ cup heavy cream in a small saucepan over low heat just until bubbles form.

Return the tempered mixture to the saucepan and cook over low heat for about 5 minutes, stirring constantly until the mixture thickens and coats the back of a spoon.

Take 80g of high-quality white chocolate and chop it into small pieces for even melting. Incorporate the chopped white chocolate into the warm egg mixture, stirring until completely dissolved and smooth.

In a clean mixing bowl, whip the remaining heavy cream until you reach medium-stiff peaks, which should take about 3-4 minutes.

Carefully fold the whipped cream into the cooled chocolate mixture in three separate additions, ensuring to maintain the light and airy texture of the mousse.

In a food processor, combine flour, salt, cayenne pepper, cinnamon, and cold unsalted butter. Pulse until the mixture resembles coarse crumbs.

Preheat your oven to 190°C (375°F). Roll out the chilled dough on a floured surface and carefully transfer it to a tart pan. Blind bake for 15 minutes.

Once the crust is completely cool, pour the light and airy mousse into the crust, smoothing the top with a spatula. Cover the tart with plastic wrap and refrigerate for at least 4 hours.

When ready to serve, garnish your mousse tart with white chocolate shavings or fresh berries, slice into wedges and serve chilled.