This time of year, if you garden or subscribe to a CSA, chances are you have a few bundles of Swiss chard monopolizing your fridge. This slab galette, which could feed over 20 people as a first course, is a great way to put those bundles to use. The dough, a David Lebovitz recipe, is one of my favorites, flaky and buttery with a nice crunch thanks to the addition of cornmeal. Feel free to use the filling as a guide — thinly sliced tomatoes or other sautéed vegetables would be nice additions. The key, however, is to go light — a thin layer of whatever filling you choose is best. Also, the recipe can be easily halved and made into a more traditionally-shaped free-form galette.
UPDATE: After many issues raised in the comments regarding dough-making trouble, I have adjusted the recipe to say 4 to 8 tablespoons of ice water. Start with 4 tablespoons, and add water by the tablespoon as needed. —Alexandra Stafford
Heat the olive oil in a large sauté pan or soup pot over medium heat. Add the sliced onion and cook, stirring frequently, until lightly browned, about 10 minutes. Season with a pinch of salt. Add the garlic and pepper flakes and cook for 30 seconds. Pile the chard on top, cover the pan if you are able, and cook for 4 to 5 minutes or until the leaves begin to wilt. Uncover the pan, use tongs to rearrange the leaves and continue cooking the chard until any liquid evaporates. Taste. This is your chance to season the chard, so add more salt if necessary.
Adjust an oven rack to the center position and heat the oven to 375° F. Line a jelly roll pan with with kitchen parchment paper.
Roll the dough on a floured surface into a large rectangle, about 15- x 21-inches or about an inch or two bigger in length and width than your sheet pan. Flip the dough every so often to ensure it’s not sticking. If it is, dust the surface with more flour. Loosely fold the dough in half and half again and transfer it to the prepared baking sheet. Unfold the dough and center it to your pan.
Spread a thin layer of ricotta on the bottom of the dough, leaving a two-inch border all the way around. Spread the onion and chard mixture over top in a thin, even layer. Sprinkle the grated cheese over top. Fold the edges of the dough inward over the filling. Pinch together any tears in the dough. Mix together the egg yolk and milk and brush it over the exposed crust.
Bake until the crust has browned and the cheese has melted, 35 to 45 minutes. Slide the galette off the parchment and onto a cooling rack or cutting board. Let cool for 10 minutes. Cut the galette into 24 pieces. Serve.
Cornmeal pastry dough
In the bowl of a food processor, pulse the flour, cornmeal, sugar, and salt until blended. Add the chilled butter to the bowl and pulse until it is evenly distributed but still in large, visible pieces. Add the olive oil and pulse a few times. Add 4 tablespoons of the ice water and pulse until the dough begins to come together, adding water by the tablespoon as needed.) Dump dough out onto a piece of plastic wrap. Roughly shape the dough into a rectangle. Wrap the disk in plastic and refrigerate for at least 1 hour. (Alternatively, whisk together the flour, cornmeal, sugar, and salt in a medium bowl. Cut in butter using the back of a fork or pastry cutter. Add olive oil and 4 tablespoons of the ice water and mix until dough just comes together, adding ice water as needed.)