Step 1: In a small bowl, combine the warmed milk, active dry yeast, and 1 teaspoon of granulated sugar. Stir gently and let it sit for 5-10 minutes until foamy. This confirms the yeast is active.
Step 2: In a large mixing bowl (or stand mixer bowl), combine the remaining granulated sugar, melted butter, buttermilk, egg, vanilla extract, and salt. Add the foamy yeast mixture and mix well.
Step 3: Gradually add 4 cups of all-purpose flour and the ¼ cup of Dutch-processed cocoa powder, mixing until a shaggy dough forms. Add the red gel food coloring, a little at a time, until a vibrant red color is achieved. Continue adding remaining flour as needed, until the dough is manageable.
Step 4: Knead the dough for 5-7 minutes until it's smooth, elastic, and no longer sticky. Use a stand mixer with a dough hook or knead by hand on a lightly floured surface.
Step 5: Lightly grease a clean bowl with oil. Place the dough in the bowl, turning once to coat. Cover with plastic wrap or a clean towel and let it rise in a warm place for 1 to 1.5 hours, or until doubled in size.
Step 6: While the dough is rising, prepare the filling. In a medium bowl, combine the softened unsalted butter, light brown sugar, Dutch-processed cocoa powder, and ground cinnamon. Mix until well combined and paste-like.
Step 7: Once the dough has doubled, gently punch it down. Turn it out onto a lightly floured surface and roll it into a large rectangle, approximately 18x12 inches (45x30 cm).
Step 8: Spread the prepared filling evenly over the entire surface of the dough, leaving about a 1/2-inch border on one of the long edges.
Step 9: Starting from the long edge opposite the border, carefully roll the dough tightly into a log. Pinch the seam closed to secure it.
Step 10: Using a sharp, un-serrated knife or dental floss, slice the log into 12-14 equal-sized rolls, about 1 to 1.5 inches thick.
Step 11: Lightly grease a 9x13 inch baking dish. Arrange the sliced rolls in the prepared dish, leaving a little space between each.
Step 12: Cover the baking dish and let the rolls rise again in a warm place for another 30-45 minutes, or until visibly puffy.
Step 13: Preheat your oven to 375°F (190°C). Bake the rolls for 20-25 minutes, or until the edges are lightly golden and the centers are cooked through.
Step 14: While the rolls are baking, prepare the cream cheese frosting. In a medium bowl, beat the softened cream cheese and unsalted butter until smooth. Add the sifted powdered sugar, vanilla extract, and salt. Beat until light and fluffy. Add milk, if desired, for a thinner consistency.
Step 15: Once the rolls are out of the oven, let them cool in the pan for 5-10 minutes. Generously spread the cream cheese frosting over the warm rolls. Serve warm or at room temperature.