Maine is fertile ground for mushrooms, especially this time of year. After a late-summer rain, mushrooms burst forth, carpeting the forest floor with their spores. Some of these fungi are wonderful edibles; others are not to be touched. Foraging is best left to mycologists and others with trained eyes — and don’t expect this famously territorial bunch to lead you to their troves. Fortunately, you can find their harvests at farmers markets (or grow your own). Look for black trumpets, chicken of the woods, chanterelles, shaggy manes, hedgehogs, oysters, and boletes through summer and into fall.
Foraged Mushroom Tart
For the crust:
1¾ cups all-purpose flour
¼ teaspoon kosher salt
12 tablespoons cold butter, cut into ¼-inch cubes
2–3 tablespoons ice-cold water
For the filling:
4 tablespoons butter
2 shallots, minced
1½ pounds September mushrooms, cleaned and cut into 1-inch pieces
1 teaspoon thyme leaves
¼ cup heavy cream
5 eggs, whisked well
1 cup grated hard salty cheese, such as Parmesan or gruyère
kosher salt and freshly ground pepper
pinch of salt
1 fluted 10-inch tart pan with a removable bottom
Preheat oven to 375 degrees. To make crust, whisk together flour and salt in a medium bowl. Cut butter into flour until no piece is bigger than a pea. Add water, a tablespoon at a time, and bring dough together without overworking it. Pack it into a ball, wrap in plastic, and place in fridge for 25 minutes.
Roll out chilled dough between two sheets of parchment paper to 11 inches in diameter. Peel off one sheet of parchment and lay dough across tart pan, dough side down, then peel away second sheet of parchment. Press dough into pan and cut off excess. Place tart in fridge while you make filling.
In a large frying pan, melt butter. Add shallots and salt and cook over medium-low heat until soft and transluscent, about 5 minutes. Raise heat to medium and add mushrooms and thyme. Cook for 15–20 minutes, until mushrooms release their liquid and it mostly evaporates. Whisk heavy cream into eggs in a small bowl.
Lay the mushrooms in chilled tart in an even layer. Top with egg mixture, and sprinkle with cheese. Place tart on a sheet pan in the oven for 35–40 minutes or until golden and fully set. Serve warm or at room temperature.