Begin by beating the egg yolks with granulated sugar in a mixing bowl until pale and creamy, about 3 minutes.

Heat ¼ cup of heavy cream in a saucepan over medium heat until small bubbles form. Gradually whisk it into the yolk mixture.

Return the tempered mixture to the saucepan and cook over low heat for about 5 minutes, stirring until thick.

Finely chop the white chocolate and stir it into the warm custard until melted and smooth.

In a separate bowl, whip the remaining heavy cream until medium-stiff peaks form.

Fold the whipped cream into the cooled chocolate mixture in three additions.

In a food processor, pulse together the flour, salt, cayenne pepper, cinnamon, and cold butter.

Preheat oven to 190°C (375°F). Roll out the dough and fit it into the tart pan, then blind bake.

Once cooled, pour the mousse into the crust and refrigerate for at least 4 hours.

Garnish with white chocolate shavings or fresh berries; slice and serve chilled.