I love making savoury galettes all year round because once you have mastered the pastry crust, it's a very versatile dish that lends itself well to any seasonal combination of vegetables as well as cheese preference. This one is one of my favourites, hands down, as it balances subtle onion flavour from leeks, robustness from the squash that has been roasted with honey and chilies, as well as buttery brie that has been baked just long enough. It is delicate enough to serve as a side but also substantial enough to be served as a main for a vegetarian entree. I prefer to use acorn squash because you can eat it with the skin on after roasting (delicata squash is a great substitute here if you can find it) but if you are using another squash, such as butternut or buttercup with much firmer peels, remove them before slicing and roasting.
Pro Tip: Be sure when assembling the dough that all of your ingredients are as cold as possible, especially the butter. It is the even flecking of the cold butter throughout the pastry crust that makes it so good and flaky!
Squash and Leek Galette with Brie and Honey 9 Steps
To prepare pastry dough, in a food processor, combine the all-purpose flour, cold cubed butter, cold sour cream and salt. Pulse 5-7 times until butter begins to break up and is roughly the size of a chickpeas, the mix should still be quite crumbly. Remove the lid and scrape down any flour on the sides, place lid back on.
Continue to pulse for another 7-10 times while carefully streaming in the ice water through the feed tube. Dough should still be crumbly but begin pulling together, the butter at this point should be about lentil size. Turn over the entire mixture to a floured work surface and begin bringing dough together by pressing with hands just until it forms a puck approximately 6 inches in diameter, this will not require much effort or kneading, and the dough should remain very evenly flecked with butter. Wrap entirely in saran wrap and allow to chill in the fridge for 1-2 hours.
To prepare the filling, while the dough is chilling, preheat the oven to 375°F. In a mixing bowl combine the sliced acorn squash, honey, chili flakes, half of the kosher salt, half of the olive oil and fresh cracked black pepper. Toss well and transfer to a parchment lined baking sheet in a single layer. Bake the squash for 20 minutes until golden brown, remove and allow to cool. Turn oven to 400°F.
While the squash is roasting, cut the leeks into 1/2-inch slices, submerge in cold water to wash and then dry well. In a saute pan on medium-low heat, warm the remainder of the olive oil and butter, add in the washed and dried leeks, the remainder of the salt and fresh cracked black pepper. Cook on medium-low heat, stirring regularly until the leeks soften and develop a light golden colour, approximately 12-15 minutes. Once softened, stir in the apple cider vinegar and half of the chopped thyme leaves, transfer to a plate to cool.
While the vegetables are cooling, whisk the whole egg and milk together, set aside. Remove the pastry dough from the fridge and allow it to sit at room temperature for 5-10 minutes before rolling.
The dough should be firm but very easy to work with, you will still need to work quickly to keep the butter cold. Remove plastic wrap and turn the dough over onto a floured work surface and begin rolling out until the dough reaches 14 inches in diameter, flouring the underside of the dough and rolling pin as necessary to prevent sticking
Transfer the rolled dough to a parchment lined baking sheet, begin by spreading an even layer of the cooked leeks on the bottom of the dough leaving 2 inches of space from the edge, next layer the roasted squash. Using your hands to fold over the edges of the galette and crimp if desired, you will fold over some of the filling closest to the edge and that is ok. Brush the edges with the egg wash and bake in the preheated 400°F for 30 minutes.
After 30 minutes remove from the oven and quickly place the pieces of brie in and around the galette, return to the oven and continue baking for an additional 10 minutes or until the brie has melted and crust is a deep golden brown.
Remove the entire galette from the oven and allow to cool for 5 minutes, sprinkle with the remainder of the thyme leaves and additional drizzle of the honey as desired. Cut into wedges and serve.