Coat a large bowl with cooking spray; set aside. In another large bowl, sprinkle yeast over warm water and let stand until foamy, about 5 minutes. Add milk, eggs, granulated sugar, salt, 1/4 cup butter and 1 tablespoon zest. Gradually add flour, mixing with hands until a dough forms. Knead until dough is shiny and elastic, 3 to 5 minutes. Transfer dough to prepared bowl, turning to oil the top, cover with plastic wrap or a clean kitchen towel and let rise until doubled in bulk, about 1-1/2 hours.

For filling, in a bowl, mix together 3 tablespoons confectioners' sugar, remaining butter and zest; set aside.

Lightly coat two 12-cup standard muffin pans with cooking spray; set aside. On a well-floured work surface, knead dough 3 to 4 times to release air pockets. Using a floured rolling pin, roll out dough to an 18-by-14-inch rectangle. Brush some filling over bottom half of rectangle and fold over top half to enclose. Brush some filling over top, as above, and fold to enclose. Let rest 5 minutes. Roll out to a 16-by-10-inch rectangle and brush half with remaining filling, as above, and fold to enclose. Cut into 24 2-inch squares.

Place squares, cut side up, in prepared pans. Coat two sheets of plastic wrap large enough to cover each pan with cooking spray; place, coated side down, over pans. Tightly wrap pans with plastic wrap or foil and freeze up to 10 days.

When ready to bake, remove outside wrapping, leaving coated plastic wrap loosely over tops. Let dough thaw and rise until almost doubled in bulk, 2 to 2-1/2 hours.

Heat oven to 350F and place rack in center. Bake rolls until golden, 15 to 18 minutes. Transfer pans to a wire rack and cool 5 minutes. Transfer rolls to rack and let cool completely.

For icing, in a medium bowl, whisk together remaining confectioners' sugar and just enough juice to make a thin icing. Drizzle over rolls.