1. Make the dough: Warm the milk in a small saucepan until steaming. Dissolve the yeast in 1/2 cup warm water in a large bowl.
2. Add the milk, shortening, eggs, 1/2 cup granulated sugar, the salt and 7 cups flour; mix with a wooden spoon until combined.
3. Transfer the dough to a lightly floured surface and knead until smooth and elastic, adding up to 1/2 cup more flour if the dough is too sticky.
4. Transfer to a lightly oiled bowl and cover with plastic wrap; let rise in a warm place until doubled in size, about 1 1/2 hours.
5. Lightly oil 2 baking sheets.
6. Combine the cinnamon and the remaining 2 tablespoons granulated sugar in a small bowl.
7. Roll out the dough on a lightly floured surface into a 12-by-24-inch rectangle, with a long side facing you.
8. Spread the butter over the right half of the rectangle, leaving a 1-inch border around the edges; sprinkle with the cinnamon sugar.
9. Fold the left half of the dough over the cinnamon sugar, like closing a book.
10. Cut the folded dough crosswise into twelve 1-inch-wide strips. Take one strip and twist several times, stretching the dough a little; hold one end of the strip against a baking sheet and wind the strip around to form a coil, tucking the other end underneath. Repeat with the remaining strips, spacing the rolls about 2 inches apart on the baking sheets. Lightly cover the baking sheets with plastic wrap and let the rolls rise until doubled in size, about 1 hour.
11. Preheat the oven to 375 degrees F. Uncover the rolls and bake until lightly browned, 25 to 30 minutes. Make the glaze: Beat the confectioners' sugar, butter and salt in a bowl with a mixer on medium-high speed until combined, about 3 minutes. Slowly beat in up to 1/4 cup boiling water until pourable.
12. Drizzle over the warm rolls and top with sprinkles.
13. Photograph by Antonis Achilleos