How to Make It
Prepare the Cinnamon Roll: Cook buttermilk, butter, salt, and 1/3 cup of the granulated sugar in a small saucepan over medium-low, stirring occasionally, until butter just melts, about 4 minutes. Remove from heat; let cool to 100°F to 110°F, about 15 minutes.
Stir together warm water, yeast, and remaining 1 teaspoon granulated sugar in a small bowl. Let stand until foamy, about 5 minutes.
Place buttermilk mixture, yeast mixture, and eggs in bowl of a stand mixer fitted with a dough hook. Gradually add 3 3/4 cups of the flour, beating on medium-low speed, until a soft dough forms and pulls away from sides of bowl but still adheres to bottom of bowl, about 3 minutes. Turn out dough onto a lightly floured work surface. Knead until smooth and elastic, about 10 minutes, adding up to remaining 1/2 cup flour, about 1 tablespoon at a time, if needed (dough should be tacky, but not sticky). Place dough in a bowl lightly coated with cooking spray, turning dough to grease top. Cover bowl with plastic wrap; let rise in a warm place until doubled in size, about 1 hour.
Roll dough into a 20- x 16-inch rectangle on a lightly floured work surface. Stir together brown sugar, cinnamon, and zest in a small bowl. Sprinkle mixture over dough, pressing gently to adhere. Using a pizza cutter, cut dough lengthwise into 8 (2-inch-wide) strips. Starting at a short end of 1 dough strip, roll up dough to create a tight swirl. Stand swirled dough piece on work surface, swirl side facing up. Wrap a second dough strip around the swirled dough piece, continuing the swirl pattern. Repeat process with remaining 6 dough strips, creating 1 very large swirled dough piece (the Cinnamon Roll).
Transfer Cinnamon Roll to a 10-inch cast-iron skillet lightly coated with cooking spray. Cover with plastic wrap; let rise in a warm place until almost doubled in size, 45 minutes to 1 hour. Meanwhile, preheat oven to 350°F.
Uncover Cinnamon Roll. Bake in preheated oven until golden brown, about 30 minutes. Cover with aluminum foil; continue baking until center is cooked through and springs back when poked gently with a fork, 10 to 15 minutes. Remove from oven; let cool 5 minutes.
Meanwhile, prepare the Glaze: Beat powdered sugar, cream cheese, cranberry sauce, milk, and zest with an electric mixer fitted with a paddle attachment on medium speed until smooth, about 1 minute.
Drizzle Glaze over warm Cinnamon Roll. Serve warm, or let cool completely, about 1 hour.