Butternut Squash and Leek Galette

 

For the galette dough

5-1/2 oz. (1-1/4 cups) all-purpose flour; more for rolling

1-1/2 oz. (1/3 cup) fine or medium yellow cornmeal

1 tsp. granulated sugar

1 tsp. kosher salt

3 oz. (6 Tbs.) unsalted butter, cold, cut into 1/2-inch pieces

3 T. extra-virgin olive oil

1/4 cup cold water

For the filling

3-1/2 T. extra-virgin olive oil

1 medium butternut squash, peeled and cut into 1/4-inch-thick slices

3 thyme sprigs, plus 1 tsp. chopped fresh thyme leaves

Kosher salt

2 large leeks, trimmed, cut lengthwise into quarters, then sliced thinly crosswise to yield 2 cups

1 large clove garlic, finely chopped

1/4 tsp. crushed red pepper flakes

4 oz. fresh goat cheese

1 T. finely chopped fresh flat-leaf parsley

Freshly ground black pepper

1 large egg beaten with 2 tsp. water or cream

Flaky sea salt

Balsamic glaze, for serving (optional)

 

Pulse the flour, cornmeal, sugar, and salt in a food processor to combine. Add the butter. Pulse until the butter is distributed and pea-size crumbs form. Add the oil and water, and process just until the dough comes together. Shape the dough into a disk, wrap in plastic wrap, and refrigerate for at least 1 hour and up to 1 day.  Position a rack in the center of the oven, and heat the oven to 425°F. Line a large rimmed baking sheet with parchment, and brush the parchment with 1/2 Tbs. of the oil. Put the squash on the baking sheet in a single layer, and brush with 1 Tbs. of the oil. Add the thyme sprigs to the baking sheet, and sprinkle the squash with 1/2 tsp. kosher salt. Roast until just tender and browned in places, 20 to 25 minutes. Meanwhile, heat the remaining 2 Tbs. oil in a large skillet over medium heat. Add the leeks, garlic, pepper flakes, and a pinch of kosher salt. Cook, stirring occasionally and lowering the heat as needed, until the leeks are tender and browned in places, 5 to 8 minutes. Let cool. In a small bowl, combine the cheese, parsley, a pinch of kosher salt, and a few grinds of pepper. Crumble with your fingers to combine.  Between two sheets of lightly floured parchment, roll the dough into a 12-inch circle. The dough will be soft and the circle thin, so very carefully slide the parchment with the dough onto a large baking sheet; it’s OK if some of the dough hangs over the side for now. The dough may tear now or when folding it later; if so, it’s not a big deal. Just pinch the dough together and move on. Sprinkle half of the goat cheese mixture (about 1/2 cup) over the center of the dough, leaving a 1-inch border. Top with the leeks, then the squash, then the remaining 1/2 cup goat cheese mixture and the thyme leaves, leaving a 1-inch border. Fold the edge of the circle up and over the filling, pleating as you go. Brush the edge with the egg wash. Refrigerate for at least 30 minutes and up to 8 hours. When ready to bake the galette, position a rack in the center of the oven, and heat the oven to 400°F. Bake until the crust is browned, 30 to 35 minutes. Let cool briefly before slicing. Sprinkle with flaky sea salt and serve warm or at room temperature with balsamic glaze on the side.