Melt 2 tablespoons butter in heavy large skillet over medium-high heat.
Ingredients you will need
Butter
Equipment you will use
Frying Pan
2
Add mushrooms and sauté until soft and dry, about 5 minutes.
Ingredients you will need
Mushrooms
3
Add remaining 1 tablespoon butter to skillet, then shallot. Sauté until shallot is soft, about 4 minutes longer.
Ingredients you will need
Shallot
Butter
Equipment you will use
Frying Pan
4
Add nutmeg. Season mushroom filling with salt and pepper. Cool.
Ingredients you will need
Salt And Pepper
Mushrooms
Nutmeg
5
Line baking sheet with parchment paper.
Equipment you will use
Baking Paper
Baking Sheet
6
Roll out puff pastry onto lightly floured surface to 12x15-inch rectangle.
Ingredients you will need
Puff Pastry Sheets
Roll
7
Cut one 12x5-inch rectangle, two 11x1/2-inch strips and two 5x1/2-inch strips from pastry.
8
Place rectangle on prepared baking sheet. Pierce all over with fork. Using pastry brush, brush all strips with egg.
Ingredients you will need
Egg
Equipment you will use
Baking Sheet
Pastry Brush
9
Place short strips, egg side down, atop ends of pastry to form raised crust edge; place long strips, egg side down, atop long sides of pastry. (Mushroom filling and tart shell can be prepared 1 day ahead. Cover separately and refrigerate.)
Ingredients you will need
Mushrooms
Crust
Egg
10
Preheat oven to 400°F.
Equipment you will use
Oven
11
Bake tart shell until golden, about 15 minutes. Maintain oven temperature.
Equipment you will use
Oven
12
Spread cheese evenly over bottom of hot tart shell. Top with mushrooms.