The texture, the umami, and the natural beauty of this mushroom galette combine into a rustically elegant foraged feast. The pastry is a simple recipe, but like all pastry, needs a bit of attention. Make certain the flour, water, and butter are as cold as possible—try to avoid touching and working the dough too much, and do allow the dough to rest before rolling it out. If you are disciplined, this buttery, free form crispy crust will melt in your mouth and commingle like old friends into the rich and satisfying meaty taste of the seared mushrooms. When choosing mushrooms, note that the more varieties, the more interesting and earthy tasting the finished pie will be (albeit, one variety is just fine, too).  A sprinkling of fresh herbs over the top of the fresh-from-the-oven galette will create a pleasant, welcoming, made in advance weeknight dinner.
cuisine American
difficulty Moderate
season Fall & Winter
serves 4

Ingredients for the pastry

1 1/4 cups all-purpose flour 8 tablespoons (115 grams) unsalted butter, cut into tiny cubes 1/2 teaspoon kosher salt 1/4 cup full fat Greek yogurt 2 teaspoons freshly squeezed lemon juice 1/4 cup ice cold water

For the filling

1 pound mushrooms (chanterelle, cremini, shitake, enoki, oyster, portabello, button, etc.) Kosher salt and freshly ground black pepper 2 tablespoons unsalted butter 4 cloves garlic, finely minced 1 cup gruyère cheese, coarsely shredded 1/2 cup crème fraîche 1 egg, thoroughly whisked 4 tablespoons chopped fresh herbs (rosemary, thyme, sage) 1 small onion, chopped 2 tablespoons sherry vinegar

Directions

  1. Place the flour and the diced butter in the freezer for at least an hour.
  2. Add the flour, butter, and salt to the bowl of a food processor and pulse until combined. Add the yogurt and the lemon juice and pulse a few times to incorporate.
  3. Pour the ice water through the tube and pulse until the dough comes together. It will be sticky. Turn out on to  plastic wrap and shape into a ball. Wrap thoroughly in the plastic wrap and refrigerate for 1 to 24 hours).
  4. Place a piece of parchment paper on the counter and sprinkle flour over its surface. Roll out the ball of dough into a 12" circle. Transfer the parchment and dough to a cookie sheet, cover with plastic wrap, and place it in the refrigerator until ready for use.
  5. Heat a 10" skillet over medium heat for two minutes. Add the butter,  mushrooms, and onion. Turn the heat to medium high and saute, turning occasionally until the mushrooms are golden.
  6. Add the garlic and stir for one minute. Add the sherry vinegar and cook for 2 minutes. Toss in the remaining gruyère and 3 tablespoons of the chopped herbs, stir for another minute. Remove from heat to cool to room temperature.
  7. Mix the crème fraîche with half of the gruyère, 1/2 teaspoon salt, and a few grinds of black pepper. 
  8. Remove the galette dough from the refrigerator and spread the crème fraîche mixture over the surface leaving a 1" border.
  9. Spoon the mushrooms onto the top of the crème fraiche mixture.
  10. Fold the border of the dough around the mushroom filling, pleating the edge to make it fit.
  11. Brush the dough, top and sides, with the egg mixture. Place the galette in the oven and bake the galette until golden brown, about 40 minutes. 
  12. Sprinkle the remaining herbs over the hot galette. Serve hot or at room temperature.