Mascarpone, a buttery-rich fresh cows-milk cheese, is a favorite throughout Italy. Look for it in the cheese section of large supermarkets or Italian markets. You can make the torte well ahead of time and freeze itsimply cool, cover with plastic wrap, place in a large plastic freezer bag and freeze up to 6 weeks. Thaw completely in the refrigerator overnight for serving.
- Preheat oven to 350°F. Grease 9-inch round tart pan with removable bottom and set aside.
- In small, heavy saucepan, melt chocolate and butter over low heat, stirring often. Remove from heat.
- In medium bowl, using an electric mixer, beat eggs and vanilla on medium speed, 30 seconds. Gradually add sugar and beat 1 minute. Beat in chocolate mixture, stopping occasionally to scrape down sides of bowl with a rubber spatula. Reduce mixer speed to low. Beat in flour and salt until just blended. Spread batter evenly in prepared pan.
- Place cheese in small bowl and stir well with fork. Drop by teaspoonfuls randomly over surface of batter in pan. Using a sharp knife, swirl cheese mixture into chocolate mixture to create marbled effect.
- Bake until just set in center, 20 to 25 minutes. Transfer pan to wire rack to cool completely. Remove side of pan, cut into wedges and serve.