Celeriac, Gruyère & Potato Tart
Preheat oven to 375 degrees F. Line a large rimmed baking sheet with parchment paper or a silicone baking mat.Advertisement
Roll puff pastry on a lightly floured surface into a 12-by-10-inch rectangle. Transfer to the prepared pan.
Combine Gruyère, mascarpone, Parmesan, shallot and thyme in a small bowl. Spread the mixture evenly over the pastry, leaving a 1/2-inch border. Using a sharp paring knife, lightly score the border. Toss potatoes and celeriac with oil in a large bowl. Arrange the vegetables, slightly overlapping, in a single layer over the cheese mixture. Sprinkle with salt and pepper.
Bake the tart until the crust is golden brown and the vegetables are tender, 40 to 45 minutes. Garnish with more thyme, if desired. Serve warm or at room temperature.
Equipment: Parchment paper, mandoline