Instructions
- Prepare the Pâte Brisée: In a food processor, pulse together the flour and salt. Add the cold butter and pulse until the mixture resembles coarse crumbs. Gradually add ice water, pulsing until the dough just comes together. Flatten into a disk, wrap in plastic wrap, and refrigerate for at least 1 hour.
- Prepare the Filling: Heat the clarified butter in a large skillet over medium-low heat. Add the onions and cook, stirring occasionally, until deeply caramelized, about 30-40 minutes. Add the potato slices and cook for another 5-7 minutes, stirring gently. Season with fleur de sel and white pepper.
- Assemble the Tart: Preheat oven to 375°F (190°C). Roll out the pâte brisée on a lightly floured surface and line a 9-inch tart pan with a removable bottom. Trim the edges. Arrange the potato and onion mixture in the tart shell, overlapping the slices. Drizzle with crème fraîche and black truffle oil. Bake for 30-35 minutes, or until the crust is golden brown and the potatoes are tender.
- Finish and Serve: Let cool slightly. Garnish with finely shaved black truffle before serving.
