Heat a glug of olive oil in a large skillet over medium heat. Add the mushrooms, season lightly with salt and pepper, and cook, stirring, until very soft and fragrant, about 8 minutes.
Scoop the mushrooms out into a bowl. Add another 1 tablespoon oil to the skillet, add the leeks, season lightly with salt and pepper, and reduce the heat so that the leeks cook slowly. (If the leeks seem dry, you can cover the pan to capture the steam, which will help them soften up; add a spoonful of water if you need even more moisture.) Cook until they are fairly soft and fragrant, but not at all browned, about 3 minutes.
Add the cabbage to the skillet, season with salt and pepper, and pour in 1/4 cup water. Cover the skillet and cook over medium heat until the cabbage has wilted, about 5 minutes. Uncover and cook the cabbage, tossing frequently, until it’s very tender and starting to turn golden, another 8 minutes or so.
Add the vinegar, Worcestershire, mustard, Parmigiano, a big squeeze of lemon juice, and a shake of hot sauce and toss to combine. Taste and adjust the salt, pepper, hot sauce, or lemon juice until the mixture is highly savory and delicious. Let the filling cool completely, preferably in the refrigerator (you can’t assemble the pies if the filling is warm).
To assemble the hand pies, divide the dough into 8 pieces. Gently shape each piece into a round and flatten the round by pressing with your fingertips until you have a disk that’s about 3 inches across. If the dough is sticking as you’re doing this, dust it or your hands with flour.
Lightly flour the work surface and roll the disk into a round about 7 inches in diameter; it’s okay if it isn’t perfectly round. Scoop out one-eighth of the filling and pile it onto the lower half of the dough round, leaving a 1-inch border all around.
Brush the border lightly with water using a pastry brush or your fingertips. Fold over the top half of the dough round, tucking it nicely around the filling, then press gently to seal the two layers of dough. Starting on one end, fold the edge over in small pleats, pressing firmly to seal.
Work your way around the edge until the pie is fully sealed. Repeat with the rest of the dough and filling. Alternatively, crimp by pressing the edges with a fork. (If your kitchen is warm, pop the finished pies in the refrigerator as you work on the rest.) Chill for at least 30 minutes.
When ready to bake, heat the oven to 375°F.
Cut three decorative slits into the top of each pie and arrange the pies on a heavy baking sheet. Bake until the pastry is an even, rich light brown (be sure to check the underside of the pies), 30 to 40 minutes. Some juices from the filling may bubble through the seams or slits; that’s fine.
Let the pies cool on a rack and serve warm.
You can bake ahead, cool, and then reheat for 10 minutes or so in a 375°F oven.
Excerpted from Six Seasons by Joshua McFadden (Artisan Books). Copyright © 2017. Photographs by Laura Dart and A.J. Meeker.
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