From King Arthur Flour
Ingredients:
Crust: 1 1/2 cups all-purpose flour 1 tablespoon za’atar 1/2 teaspoon table salt 1/2 teaspoon baking powder 12 tablespoons cold unsalted butter, cut in 1/2-inch cubes 6 tablespoons sour cream Filling: Large delicata squash Salt and pepper, to taste 3 tablespoons olive oil, divided 1 cup diced yellow onion 1 tablespoon white wine vinegar 1/2 cup goat cheese 1/3 cup sour cream 1/2 teaspoon za’atar
Preparation:
In a large bowl, whisk together flour, za’atar, salt and baking powder. Add butter and use hands to separate the cubes and toss with flour mixture. Work butter into flour with your fingers or a pastry cutter until mixture is crumbly. Add the sour cream and stir until large clumps of dough begin to form. Use your hands to knead and squeeze the dough together into a cohesive mass.
On a clean work surface, shape the dough into a square about 1″ thick and refrigerate it for 30 minutes or up to 48 hours. If you let the dough chill for longer than 30 minutes, allow it to rest at room temperature for 5 to 10 minutes before rolling. While the dough chills, make the filling.
To make the filling: Preheat the oven to 425 degrees and position a rack in the lower third.
Rinse the squash and pat dry. Cut the ends off, then cut in half lengthwise and remove the seeds. Cut each squash into 1/4″-thick half-moon slices and place them in a large bowl. Add 2 tablespoons olive oil and toss to coat. Season with salt and pepper to taste.
Arrange the squash in a single layer on a lightly greased or parchment-lined baking sheet. Roast the squash for 10 to 15 minutes.
Remove the squash from the oven and allow it to cool until you’re ready to assemble the galette. (The squash can be roasted ahead of time and refrigerated for up to 4 days.)
In a medium saucepan set over medium-high heat, combine the onion and the remaining 1 tablespoon olive oil. Cook the onions, stirring occasionally, for 10 to 15 minutes until browned. Turn off the heat, add the vinegar, and stir to combine.
Remove the pan from the stove and transfer the onions to a medium bowl to cool slightly. You should have about 1/2 cup of cooked onions.
To the bowl with the onions, add the goat cheese, sour cream, za’atar, 1/8 teaspoon salt, and a pinch of black pepper and stir to combine. (The goat cheese mixture can be made ahead of time and refrigerated for up to 1 week.)
To assemble the galette: When you’re ready to bake, preheat the oven to 425 degrees. Meanwhile, roll out the dough on a lightly floured work surface until it forms a rectangle about 11″ x 15″ in size. Transfer the dough to a parchment-lined baking sheet and poke (dock) the dough all over with the tines of a fork.
Spread the goat cheese filling evenly over the dough, leaving a 1/2″- to 1″-wide bare border around the edges. (A small offset spatula is a helpful tool here.)
Arrange a single layer of roasted squash on top of the filling, pressing gently to adhere.
Use a bench knife or chef’s knife to make a diagonal cut in each of the corners of the dough, about 1″ to 1 1/2″ long. Fold the long sides of dough up and over the filling, then fold the short sides of dough up and over the filling. At the corners, tuck any overhanging dough underneath the galette.
Brush the exposed edges of the galette with egg wash. Bake the galette for 30 to 35 minutes, until the crust is golden brown. Remove from the oven and allow it to cool for 5 to 10 minutes on the pan. Sprinkle with parsley, cut into slices, and serve warm or at room temperature.