1 (17 1/4 oz.) pkg. frozen puff pastry sheets (2 sheets), thawed
6 tbsp. unsalted butter, room temperature
1/2 c. sugar
3/4 c. hazelnuts or filberts (3 oz.), toasted, husked, finely ground
2 tbsp. flour
1 tsp. vanilla
2 eggs
1 3/4 oz. bittersweet (not unsweetened) or semi-sweet chocolate, cut into sm. pieces

Preheat oven to 400 degrees. Cut 1 pastry sheet into 9 1/2" diameter round. Transfer to heavy large cookie sheet; chill.

Using electric mixer, cream butter and sugar in medium bowl until fluffy. Mix in nuts, flour and vanilla. Mix in 1 egg. Spread filling evenly over chilled pastry round, leaving 1/2" border of edge. Arrange chocolate pieces over filling, spacing evenly. Chill 15 minutes.

Beat remaining egg to blend in small bowl. Cut second pastry sheet into 9 1/2" diameter round. Brush border of filled pastry with beaten egg. Top with second pastry round, pressing edges together firmly to seal. Crimp edges decoratively. Brush pastry with beaten egg. Cut small vent hole in center. Bake until puffed and golden brown, about 25 minutes. Cool 10 minutes on cookie sheet. Transfer to platter. Serve warm or at room temperature. 8 servings.