Pithiviers are traditionally made with two layers of puff pastry encasing a sweet or savory filling. The top layer is often decorated with a spiral design made by drawing the point of a knife lightly across the pastry, but in this veggie-stuffed version, I used a dough lattice as a decorative element instead. The effect is really lovely and thanks to a lattice cutter, it’s much easier to accomplish than you might think. Sunflowers made from dough petals with mushroom cap centers round out the show-stopping presentation.
a lattice cutter, 1 1/2-inch petal cutter, 1-inch petal cutter and 1-inch round cutter (optional)
Preheat the oven to 400 degrees F with a rack in the middle position.
Place the butternut squash on a rimmed baking sheet, toss with the olive oil and spread out into a single layer. Season with salt and pepper. Place the red and yellow pepper halves cut-side down on another rimmed baking sheet.
Place both baking sheets on the middle rack and roast until the squash has softened and browned and the peppers have charred, about 25 minutes. Set the vegetables aside. When the peppers are cool enough to handle, peel off the skin and discard. Slice the peppers into 1/2-inch strips, season lightly with salt and pepper and set aside.
Melt the butter in a medium saucepan over medium heat. Add the onions and mushrooms and cook until soft and browned and any liquid is evaporated, 8 to 10 minutes. Add the sage and thyme, season with salt and pepper and mix thoroughly. Set the mushroom mixture aside to cool.
Bring 3 cups water to a boil in a small saucepan. Place the spinach in a colander in the sink and pour the boiling water over the leaves to wilt them. Shake the colander to drain the water, then lay the spinach on paper towels and pat dry, removing as much of the remaining water as possible. Set the spinach aside.
To make the base for the pithivier, lay 1 sheet of the puff pastry on a lightly floured piece of parchment paper set on a baking sheet. Using an upside-down bowl with a 10-inch-wide rim as a guide, cut out a 10-inch circle from the pastry using a sharp knife. Gather the scraps and set aside for another use (see Cook’s Note).
Spread the cooled mushroom mixture over the puff pastry base, leaving a 1/2-inch border all around. Arrange the cooled butternut squash cubes on top of the mushroom mixture. Sprinkle the goat cheese over the squash, then top with the reserved spinach and roasted pepper strips. Wet your hands and gently mold the filling into a dome shape, then set aside.
To make the puff pastry top, lay another sheet of puff pastry on a lightly floured piece of parchment paper. Using an upside-down bowl with a 12-inch-wide rim as a guide, cut out a 12-inch circle from the pastry using a sharp knife. Gather the scraps and add to the existing scraps.
Whisk together the egg yolk and water in a small bowl. Brush the egg wash around the border of the 10-inch pithivier base. Gently lay the 12-inch circle over the base so that it completely covers the filling. Press down all around the edges of the pithivier to seal the filling inside, making sure to press out any air bubbles as you go. Don’t worry if the base is no longer a perfect circle. You will trim it later. Egg wash the entire top of the pithivier and set aside.
Cut the remaining sheet of puff pastry in half lengthwise so that you have two pieces, each approximately 6 by 15 inches. Set 1 piece aside. Firmly roll a lattice roller lengthwise down the other piece. Repeat until the entire piece has been cut with the lattice.
Use your fingers to gently pull the lattice apart, starting from the middle of the lattice and working your way out. As you work, use a sharp knife to open up any sections where the cutter did not go all the way through the lattice. Gently drape the lattice over the pithivier, then use your hands to smooth it into shape, ensuring that the entire top is covered.
Place the 10-inch-wide bowl used earlier over the pithivier and use a sharp knife to trim the base into a neat 10-inch circle. Add any dough scraps to the existing scraps. Use the back of the knife to make 1/2-inch-deep vertical indentations around the base. Evenly egg wash the entire surface of the pithivier, being careful not to let the egg wash pool in the lattice as that will create uneven browning.
Stir together the turmeric and 2 tablespoons water in a small bowl until completely combined. Lay the remaining 6-by-15-inch piece of pastry on a piece of lightly floured parchment paper and roll out the pastry as thinly as possible. (That will help ensure that the petals do not puff up and distort in the oven.) Using a small pastry brush, brush the top of the sheet with the turmeric mixture. Don’t worry if the mixture seems to go on a bit unevenly. The variegated shades of yellow will look lovely once you begin to make the flowers.
Using a 1 1/2-inch and 1-inch petal cutter, cut petals from the sheet of pastry. The number of petals you cut depends on how many flowers you want to make (and what size you’d like them to be). To create the 4 large flowers and 6 small flowers shown in the picture, you will need to cut sixty-six 1-inch petals and forty-four 1 1/2-inch petals.
To assemble a flower, dab a small amount of egg wash on the lattice. Place 6 petals in a circle, ensuring that the top of the petals meet in the center. Place another dab of egg wash in the center of the flower and add a second layer of 5 petals, offsetting each slightly from the one below it. Place another dab of egg wash in the center and attach a mushroom cap (see Cook’s Note). Press firmly to adhere the cap to the petals. Transfer the finished pithivier to the freezer for at least 2 hours and preferably overnight.
When you are ready to bake the pithivier, preheat the oven to 350 degrees F with a rack in the lower-middle position.
Bake the pithivier until golden brown, 55 to 60 minutes. Allow to cool for about 15 minutes. Serve warm or at room temperature. Leftovers can be stored, tightly wrapped, in the refrigerator for up to 48 hours.
Leftover scraps of puff pastry can be rolled together and reused for another purpose. Store it, tightly wrapped in plastic wrap, in the refrigerator for up to 48 hours or in the freezer for up to 3 months. If you can’t find button mushrooms small enough for the centers of the flowers, use a 1-inch round cutter to punch out circles from larger mushrooms.