1 sheet puff pastry (9-inch square), thawed but cold
1 egg, beaten with a little water
1/2 cup grated Parmigiano Reggiano cheese
2 baking potatoes (1 1/2 pounds), peeled and cut into 1/2-inch cubes
4 cups chopped kale or swiss chard
2 tablespoons extra virgin olive oil (EVOO)
2 tablespoons butter
2 1/2 pounds cremini mushrooms, halved
3 cloves garlic, chopped
7 sprigs sage, thinly sliced
1/2 cup marsala or cooking wine
1 cup heavy cream
8 ounces ripe brie cheese, rind discarded, cut into small pieces
Pre-heat the oven to 425°. Roll out the puff pastry into a 12-inch square. Set aside four 2-cup bowls; invert 1 bowl onto the pastry and cut out 4 rounds. Place on a parchment-paper-lined baking sheet and brush with the egg. Sprinkle with half of the parmigiano-reggiano cheese. Bake until golden, 12 minutes. Let cool.
In a large saucepan, add the potatoes and enough water to cover. Bring to a boil, salt the water and cook until tender, 7 minutes. Add the kale and cook for 2 minutes; drain.
In a large skillet, heat 2 tablespoons EVOO and the butter over medium-high heat. Add the mushrooms and cook, stirring occasionally, until tender, about 12 minutes. Add the garlic and sage; season with salt and pepper. Cook until the garlic is slightly softened, about 3 minutes. Add the wine and cook until slightly reduced, about 1 minute. Add the cream and cook, stirring, for 1 minute. Remove from the heat and fold in the brie and remaining parmigiano-reggiano until melted. Stir in the potatoes and greens. Fill the bowls with the mushroom mixture and top with the crust.