FILLING:
Combine ricotta cheese, sugar and vanilla extract. Beat until smooth. (about 10 minutes with an electric mixer on medium-high speed) Stir in citron and semi-sweet chocolate pieces and mix thoroughly. Place mixture in the refrigerator to chill.
SHELLS:
Sift together flour, sugar, cinnamon, and salt in a bowl.
Using pastry blender, cut in flour mixture and 3 tablespoons shortening. Stir in 2 well-beaten eggs. Blend in, 1 tablespoon at a time, 2 tablespoonswhite vinegar and 2 tablespoons cold water until pieces are small pea-sized.
Turn dough onto a lightly floured surface and knead. Wrap in waxed paper and chill in refrigerator for 30 minutes.
FINISH:
Set out deep saucepan or automatic deep-fryer for deep-frying and heat fat to 360 degrees. From cardboard, cut an oval pattern 6 x 4 1/2 inches. Blanch, finely chop, and set aside 1/4-1/2 cup pistachio nuts. Roll chilled dough 1/8 inches thick on floured surface. With cardboard pattern and pastry cutter, cut ovals from dough.
Wrap dough lossely around tubes just lapping over opposite ends. Seal edges by brushing with slightly beaten egg white. Press edges together to seal.
Fry only as many Cannoli shells as will float uncrowded one layer deep in the fat. Fry about 8 minutes, or until golden brown, turning occasionally during frying time. Drain over fat before removing to absorbent paper. Cool completely.
When ready to serve, fill with ricotta filling. Sprinkle ends of cannoli with chopped nuts and dust shells with sifted confectioner's sugar.
YIELD: 16-18 Cannoli