Potato-Gruyère Tart
Serve this savory puff pastry tart as an elegant appetizer or a vegetarian main.This simple, yet impressive savory tart combines cheese, potatoes, and thyme on a crispy puff pastry crust. Using store-bought puff pastry and a bit of Dijon mustard makes this tart easy enough for a weeknight but impressive enough for company. Cut the tart into 16 pieces for an elegant appetizer or slice into larger wedges and serve it with a salad for a light lunch, or holiday vegetarian main.
Servings: 16 (1 tart)
Ingredients
- 1 pound medium-size (about 4 ounces each) Yukon Gold potatoes, scrubbed and cut into 1/8-inch slices
- 2 tablespoons, plus ¼ teaspoon kosher salt divided
- 2 tablespoons extra-virgin olive oil
- 1 large yellow onion thinly sliced
- 2 tablespoons water
- 1 sheet frozen puff pastry (from 1 [17.3-ounce] package), thawed
- All-purpose flour
- ¼ cup heavy whipping cream
- 2 tablespoons fresh thyme leaves plus more for garnish
- 1 teaspoon Dijon mustard
- ⅛ teaspoon ground nutmeg
- 6 ounces Gruyère cheese shredded (about 1½ cups), divided
- Black pepper
Instructions
- Preheat oven to 400°F with rack in lower third position.
- Line a rimmed baking sheet with parchment paper. Place potatoes and 2 tablespoons of the salt in a large saucepan; add water to cover by 1 inch. Bring to a boil over high; reduce heat to medium, and cook, undisturbed, until potatoes can be pierced using tip of a knife but are still firm, 2 to 3 minutes. Drain well; let stand until cool enough to handle, about 10 minutes.
- Return saucepan to medium heat; add oil, and heat until shimmering. Stir in onion and remaining ¼ teaspoon salt; cook, stirring occasionally, until translucent, about 3 minutes. Reduce heat to medium-low; cover and cook, stirring occasionally, until onion begins to soften and brown around edges, about 18 minutes. Uncover and increase heat to medium-high; stir in water, scraping up any browned bits from bottom of saucepan. Cook 2 minutes, stirring often, until onion is browned and caramelized. Let stand until cool, about 5 minutes.
- Roll puff pastry on a lightly floured work surface to a 14 x 12-inch rectangle. Transfer to prepared baking sheet. Lightly score a border around perimeter of puff pastry using a paring knife, about 1 inch from edges. Prick pastry all over using a fork, leaving a 1-inch border around edge.
- Stir together cream, thyme, Dijon mustard, nutmeg, and 1 cup of the Gruyère in a medium bowl until combined. Spread cheese mixture in an even layer inside scored border of pastry. Arrange potato slices in overlapping layers over cheese mixture inside border; top evenly with caramelized onions. Top with remaining ½ cup Gruyère.
- Bake in preheated oven until pastry is puffed and deep golden brown, about 30 minutes. Transfer baking sheet to a wire rack, and let cool 5 minutes. Garnish with black pepper and additional thyme.
- Slice into 16 (3¼ x 3-inch) pieces; serve warm or at room temperature.
