Mushrooms Stuffed Brie Baked en Croute

Preheat oven to 450 degrees F. In a large skillet, heat butter until melted. Add onion; cook, stirring occasionally, until tender, about 6 minutes. Add mushrooms, sherry, nutmeg, salt and black pepper; cook until mushrooms are tender and liquid evaporates, about 5 minutes; let cool slightly.

On a lightly floured surface using a rolling pin, roll 2 puff pastry sheets to 1/8-inch thickness. Place 1 sheet on a shallow baking sheet; top with bottom half of brie. Spread cooled mushroom mixture over the cheese, top with remaining cheese. Pull up pastry over brie and trim, leaving 1 inch pastry folded over brie. Brush the folded edge with egg. On the second sheet of pastry, using the diameter of brie as your guide, cut out a circle of pastry the same size as the brie; place on top of brie; press down to seal onto pastry "rim". Brush all pastry with egg. Cut remaining scraps of dough into mushroom shapes; press on top of pastry; brush with egg. With the back of a knife, gently score side of pastry with vertical marks, being careful not to pierce dough. Refrigerate 15 minutes to set egg wash. Bake until puffed and golden, about 20 minutes. Serve immediately.