Cloud Nine

For the crust:
Combine the flour, sugar, and salt in the bowl of a food processor and pulse a few times to combine. Add the butter and shortening and pulse until the mixture resembles coarse crumbs. With the machine running, add the water in a slow, steady stream, blending just until the dough comes together. If the dough is too dry, add more water 1 tablespoon at a time.

Transfer the dough to a lightly floured work surface and shape into a flat disk. Wrap in plastic wrap and chill the dough in the refrigerator for at least 1 hour, or overnight.

Preheat the oven to 375°F. Lightly grease a 9-inch round tart pan with a removable bottom. Place the dough on a lightly floured work surface and roll into an 11-inch circle, about 1/8-inch thick. Place the dough over the tart pan and gently press the dough into the edges of the mold. Freeze for 10 minutes. Remove crust from the freezer and line it with aluminum foil and fill with pie weights. Bake for 15 to 20 minutes, until the edges are lightly browned. Remove the foil and pie weights and bake for another 8 to 10 minutes, until golden brown all over. Remove from the oven and let it cool completely.

For the caramel:
Combine the heavy cream and salt in a small saucepan. Scrape the seeds from the vanilla bean into the pan and add the whole bean. Bring to a simmer over low heat and stir until the salt is dissolved.

Meanwhile, combine the sugar, water, and corn syrup in a medium saucepan over high heat, stirring until the sugar is dissolved. Bring to a boil and cook for 6 to 8 minutes, until a candy thermometer registers 360°F and the mixture is a deep amber color. Remove from the heat and let it sit for 1 minute. Add the warm cream and stir until smooth. Remove and discard the vanilla bean.

Pour the caramel into the cooled tart shell and spread evenly. Chill in the refrigerator for about 45 minutes, until the caramel is set.

For the custard:
Combine the granulated sugar and water in a small saucepan over high heat, stirring until the sugar is dissolved. Bring to a boil and cook for 5 to 6 minutes, until the mixture turns a light golden color. Remove from the heat and let it cool for 1 minute. Stir in the cream, then set aside and let it cool completely.

Whisk the egg yolks in a large heatproof bowl. Whisk together the milk, brown sugar, cornstarch, and salt in a medium saucepan over medium-high heat and cook until the mixture comes to a gentle boil. Remove from the heat and whisk in the cooled caramel. Slowly add the warm milk mixture to the egg yolks, whisking vigorously until well combined. Return the mixture to the saucepan and place over low heat and cook, stirring constantly, until the custard is thick enough to coat the back of a wooden spoon. Remove from the heat and stir in the vanilla. Spread the custard into the pie shell. Chill for about 2 hours, until cold.

For the meringue:
Place the egg whites, cream of tartar, and salt in the bowl of an electric mixer fitted with the whisk attachment. Beat on medium speed for 2 to 3 minutes, until frothy. Increase the mixer speed to medium-high and gradually add the sugar, beating for another 2 to 3 minutes, until stiff, thick, and shiny. Spread the meringue over the surface of the pie, spreading it all the way to the edges.