Simple and elegant, this tart features a creamy white chocolate and mascarpone filling in a buttery macadamia shortbread crust.
To make the crust: Place the nuts in the bowl of a food processor with 1/2 cup of the flour. Pulse until the nuts are finely ground, but not so much that they become pasty.
In a large mixing bowl, beat together the butter and sugars until fluffy. Add the vanilla and beat to combine. Scrape the sides and bottom of the bowl. Mix in the salt, flour, and nut/flour mixture. The mixture will look dry and crumbly at first, but keep mixing and it will come together to form a stiff dough.
Press the dough into and up the sides of an ungreased 9" round tart pan. Chill for 30 minutes while you preheat the oven to 375°F.
Prick the chilled tart dough all over with a fork, then line the shell with parchment and pie weights or dried beans. Place the tart pan on a baking sheet and bake it for 15 minutes.
Remove the pan from the oven, remove the weights and parchment, and return to the oven for 12 to 15 minutes, until the center is golden brown. Remove from the oven and cool completely.
To make the filling: Heat the heavy cream to a simmer and pour it over the white chocolate in a medium bowl. Let sit for 2 minutes, then whisk until completely smooth (the mixture will look thin). Chill for 1 hour.
To assemble: Whip the chilled cream/white chocolate mixture until it thickens and the color changes from ivory to white. Add the mascarpone and whip for 30 to 60 seconds, until smooth.
Spread the filling in the cooled shell. Garnish with chopped macadamia nuts.
Refrigerate the pie, well wrapped, until ready to serve. Refrigerate any leftovers.
