Preparation

1. 1. On a lightly floured surface, roll the dough into a 10-inch disk. Fit into an ungreased 9-inch tart pan or pie plate and chill for 20 minutes. Prick the dough evenly all over with a fork, making sure not to go entirely through the dough.
2. 2. Preheat oven to 350°F with the rack in the lower position. Line the pie shell with parchment and fill with dried beans, rice or pie weights. Bake the crust for about 20 minutes, until the dough beneath the parchment is dry. Remove the parchment with weights and bake the shell for an additional 8 to 10 minutes, or until shell is lightly browned. Remove from oven and cool completely.
3. 3. In a heatproof bowl set over a pot of simmering water, melt the chocolate. Pour the chocolate into the cooled tart shell and smooth with an offset spatula to cover the bottom evenly. Chill the tart in the freezer for 5 minutes or until chocolate has hardened.
4. 4. Put the heavy cream in a medium to large mixing bowl and whip, using Speeds 1 to 2, until soft peaks form; reserve. In another medium bowl, whip the mascarpone with the sugar, salt, and vanilla extract, using Speeds 1 to 3, until lightened and ingredients are fully combined. Stir in a small amount of the whipped cream tolighten the mixture a bit, and then gently fold in the remaining whipped cream, using a large flexible spatula, into themascarpone mixture, one-third at a time, until completely incorporated.
5. 5. Spread the mascarpone cream into the prepared shell on top of the chocolate, smoothing the top with an offset spatula. Decoratively arrange the berries over the cream, covering as much of the cream as possible. Chill the tart in the refrigerator for 30 minutes before serving.