1 15-ounce carton ricotta cheese

3/4 cup powdered sugar

1 teaspoon vanilla

1 ounce bittersweet or semisweet chocolate, grated

4 ounces bittersweet or semisweet chocolate, chopped

1 tablespoon shortening

12 to 14 purchased cannoli shells

3/4 cup finely chopped pistachio nuts

1 cup whipping cream

1. For filling, in a medium bowl, stir together ricotta cheese, powdered sugar, and vanilla until almost smooth. Stir in 1 ounce bittersweet chocolate. Cover and chill up to 6 hours.

2. Meanwhile, in a small saucepan, heat and stir 4 ounces bittersweet chocolate and the shortening over low heat until melted. Remove from heat. Transfer to a small bowl. Dip both ends of the cannoli shells in chocolate, letting excess drip off. Sprinkle chocolate ends with pistachio nuts. Place on a wire rack placed over waxed paper to dry (about 45 minutes).

3. When chocolate is dry, in a medium bowl, beat whipping cream at medium speed of an electric mixer or with a wire whisk until stiff peaks form. Fold into the ricotta mixture. Spoon filling into a decorating bag fitted with a large round or open star tip (or spoon into a resealable plastic bag; seal bag. Snip off a small corner of the bag). Pipe filling into shells. Cover and chill up to 2 hours.