For the Shells: In a large bowl, combine the flour, cinnamon, sugar, and cocoa powder and cut in the butter with 2 knives or a pastry cutter, until the mixture resembles coarse crumbs. Add the Limoncello and shape the dough into a ball. Wrap the dough in plastic and refrigerate.
2 quarts Canola Oil (for frying)
For the Filling: In a 3 1/2-quart pot, heat the canola oil to 350 degrees F.
16 ounce Fresh Sheep's Milk or Cow's Milk Ricotta (drained for 1-hour in a cheesecloth-lined conical sieve) 1/2 cup Superfine Sugar 1 tablespoon Vanilla 4 tablespoons Candied Orange Zest 1/4 cup tiny Chocolate Chips
In a mixing bowl, stir together the ricotta, sugar, vanilla, orange zest and chocolate chips until well-mixed. Spoon into a pastry bag with an open tip and place in the refrigerator.
Remove the dough from the refrigerator and divide into 4 pieces. Roll one piece onto a flat surface with a rolling pin to a 1/16-inch thickness. Using a cookie cutter, cut 4-inch circles from the dough. Using the rolling pin, roll each circle into an oval and wrap each oval lengthwise around a metal form, sealing the edges with egg whites. Flare the edges open with fingers.
Gently drop the cannoli shells into the hot oil and fry until dark golden brown, about 2 to 3 minutes. Remove from the oil with a slotted spoon and allow to drain on paper towels. When the cannoli are cool enough to touch, twist the molds away from the shells. The shells may be made one day in advance and allowed to rest, unfilled and uncovered.
Confectioner's Sugar for dusting (optional)
To complete the cannoli, stuff with ricotta cream, dust with powdered sugar and serve.