1 1/4 cup all-purpose flour
1/2 cup whole wheat flour
1 tablespoon sugar
3/4 teaspoon salt
10 tablespoons unsalted butter, cut into 1/2-inch pieces and chilled
7 tablespoons ice water
1 teaspoon distilled white vinegar
1 1/4 pound shiitake mushrooms, stemmed and sliced thin
5 teaspoons olive oil
1 pound leeks, white and light green parts only, sliced 1/2 inch thick and washed thoroughly (3 cups)
1 teaspoon minced fresh thyme
2 tablespoons creme fraiche
1 tablespoon Dijon mustard
Salt and Pepper
3 ounces Gorgonzola cheese, crumbled (3/4 cup)
1 large egg, lightly beaten
2 tablespoons minced fresh parsley
1. FOR THE DOUGH. Pulse all-purpose flour, whole-wheat flour, sugar and salt together in food processor until combined, 2 to 3 pulses. Add butter and pulse until it forms pea-sized pieces, about 10 pulses. Transfer mixture to medium bowl.
2. Sprinkle water and vinegar over mixture. With rubber spatula, use folding motion to mix until loose, shaggy mass forms with some dry flour remaining (do not overwork). Transfer mixture to center of large sheet of plastic wrap, press gently into rough 4-inch square and wrap tightly. Refrigerate for at least 45 minutes.
3. Transfer dough to lightly floured counter. Roll dough with palm of hand for about a minute until you can see that the small butter chunks are beginning to disappear and looks well formed and solid. Re-wrap in plastic wrap into another 4-inch square and refrigerate another 45 minutes up to 2 days.
4. FOR THE FILLING. Microwave mushrooms in covered bowl until just tender, 3-5 minutes. Transfer to colander to drain, return to bowl. Meanwhile, heat 1 tablespoon oil in 12 inch skillet over medium heat until shimmering. Add leeks and thyme, cover and cook, stirring occasionally, until leeks are tender and beginning to brown, 5 to 7 minutes. Transfer to bowl with mushrooms. Stir in creme fraise and mustard. Season with salt and pepper to taste. Set aside.
5. Adjust oven rack to lower-middle position, place pizza stone (or upside-down cookie sheet) on rack and heat oven to 400 degrees. Remove dough from refrigerator and let stand at room temperature for 15 minutes. Place a large piece of parchment paper out and begin to roll the dough out onto it. Try to form a 14-inch circle about 1/8 inch thick. Trim edges as needed. With tip of paring knife, cut five 1/4 inch circles in dough. One at center and four evenly spaced half-way from center to edge of dough. Brush top of dough with 1 teaspoon oil.
6. Spread half of filling evenly over dough, leaving 2-inch border around edge. Sprinkle with half of Gorgonzola, cover with remaining filling and top with remaining Gorgonzola. Drizzle remaining 1 teaspoon oil over filling. Gently grasp around circumference of tart, overlapping dough every 2 inches, gently pinch pleated dough to secure but do not press dough into filling. Brush dough with egg and sprinkle evenly with kosher salt. Tear parchment paper so just a bit is exposed around the edges. I used a pizza peel to transfer the galette onto the pizza stone.
7. Lower oven temperature to 375 degrees. Bake until crust is deep golden brown and filling is beginning to brown, 40 minutes. Let tart cool on baking sheet on wire rack for 10 minutes. Using offset or wide metal spatula, loosen tart from parchment and carefully slide tart off parchment onto cutting board. Sprinkle with parsley, cut into wedges, and serve.
Recipe is from Americas Test Kitchen