Puff pastry spread with Dijon mustard encases nutty Gruyère cheese in these rich palmiers baked in heart shapes.
Savory Gruyère Palmiers
- ½ (17.3-ounce) package frozen puff pastry, slightly thawed (1 sheet)
- 2 tablespoons coarse-grain Dijon mustard
- ½ cup shredded Gruyère cheese
- ½ teaspoon chopped fresh thyme
- ⅛ teaspoon ground black pepper
- 1 large egg
- 1 tablespoon water
- Preheat oven to 400°. Line a rimmed baking sheet with parchment paper.
- Using a rolling pin, roll out puff pastry sheet on a lightly floured surface into a 10-inch square. (Puff pastry should be thawed but still firm.)
- Spread mustard in an even layer onto puff pastry, leaving a 1-inch border around edges. Sprinkle evenly with cheese, thyme, and pepper.
- Mark dough at top and bottom edges at the halfway point. Fold in opposite sides of the dough square (right and left edges) so the sides are halfway from the center (a ¼ fold). Using a rolling pin, lightly roll dough to laminate. Fold opposite sides again toward center, meeting at the marked halfway point of dough square. Lightly roll dough again to laminate. Fold right half of dough lengthwise over left half of dough. Using a rolling pin, roll dough again lightly to laminate. (This will keep pastries from puffing up too much.)
- Using a sharp knife, trim and discard ends of dough stack. Cut folded dough into 10 (approximately 1-inch-wide) slices. Place slices, cut sides down, onto prepared baking sheet. Pinch bottom fold of each slice into a point. Tops of pastries should be slightly separated—this will create a heart shape when baked.
- In a small bowl, whisk together egg and 1 tablespoon water until combined. Brush tops of palmier slices with egg mixture.
- Bake until pastries are lightly golden brown, 14 to 16 minutes. Serve warm.