Wild Mushroom GaletteOctober 27, 2015
In medieval England mushrooms were considered excrementa terrae, or excrement of the earth, because of their mysterious growth and the fact that they lack visible roots. Modern European cultivation of the mushroom goes back to 1600, when French agriculturalist Olivier de Serres suggested a method in his work Le Théâtre d’agriculture et mesnage des champs (The Theater of Agriculture and Tending for the Fields), the textbook for French agriculture of the 17th century. A standby in French homes, a galette is a sweet or savory flat, freeform tart.
For the dough:
3 tablespoons buttermilk
1/3 cup ice water
1 cup flour
¼ cup yellow cornmeal
1 teaspoon sugar
½ teaspoon salt
7 tablespoons cold unsalted butter, cut into 6 to 8 pieces
For the filling:
1 pound assorted mushrooms – shiitake, oyster, porcini or Portobello
3 tablespoons olive oil
¼ cup onion, diced
1 tablespoon herbs de Provence
1 tablespoon red wine vinegar
2 cups Gruyere cheese, grated
salt and pepper
Position a rack in the lower third of the oven and preheat to 400 F. Line a baking sheet with parchment paper.
Stir the buttermilk and 1/3 ice water together in a small bowl and set aside.
Put the flour, cornmeal, sugar and salt in a bowl and stir with a fork to mix. Drop the butter pieces into the bowl and using fingers work the butter into the flour until it resembles breadcrumbs.
Sprinkle the cold buttermilk mixture over the dough, 1 tablespoon at a time, tossing with a fork to distribute evenly. Gather the dough together and chill.
Put the dough on a lightly floured work surface and roll into a 1/8-inch think circle and transfer to the baking sheet.
Meanwhile, wipe the mushrooms and thinly slice. Heat the oil in a wide skillet of medium heat. Add the onion and cook, stirring occasionally, until soft, about 4 minutes. Raise the heat, add the mushrooms and sauté until they begin to soften, about 5 minutes. Stir in the herbs and season with vinegar, salt and pepper.
Spread ¾ of the cheese over the dough, then the mushroom mixture, then top with the remaining cheese. Dip a pastry brush in water, giving the edges of the crust a light coating and bake for about 35 minutes, or until golden and cheese is bubbly. Serve warm or at room temperature.