Step 1: In a small bowl, warm the milk to about 105-115°F (40-46°C). It should be warm to the touch, but not hot. Stir in 1 teaspoon of granulated sugar and sprinkle the active dry yeast over the top. Let it sit for 5-10 minutes until foamy. If it doesn’t foam, your yeast is likely dead, and you should start over with new yeast.
Step 2: In a large mixing bowl (or the bowl of a stand mixer fitted with a dough hook), combine the proofed yeast mixture, 1/2 cup melted unsalted butter, egg, 1 teaspoon vanilla extract, and 1/2 teaspoon salt. Mix well.
Step 3: Gradually add the all-purpose flour, one cup at a time, mixing until a shaggy dough forms. If using a stand mixer, knead on medium-low speed for 5-7 minutes. If kneading by hand, turn the dough out onto a lightly floured surface and knead for 8-10 minutes until the dough is smooth and elastic. It should spring back when poked.
Step 4: Lightly grease a clean large bowl with a little oil or cooking spray. Place the dough in the bowl, turning once to coat. Cover the bowl with plastic wrap or a clean kitchen towel and let it rise in a warm place for 1-1.5 hours, or until doubled in size.
Step 5: While the dough is rising, prepare the filling. In a small bowl, combine 1/4 cup softened unsalted butter, 1 cup light brown sugar, and 2 tablespoons ground cinnamon. Mix until well combined and paste-like. Set aside.
Step 6: Once the dough has doubled, gently punch it down to release the air. Turn it out onto a lightly floured surface.
Step 7: Using a rolling pin, roll the dough into a large rectangle, approximately 12×18 inches (30×45 cm) and about 1/4 inch thick. Aim for an even thickness.
Step 8: Spread the cinnamon-sugar filling evenly over the entire surface of the dough, leaving a small 1/2-inch border on one of the longer sides clean.
Step 9: Starting from the longer side opposite the clean border, tightly roll up the dough into a log. Pinch the seam closed to seal.
Step 10: Using a sharp, un-serrated knife or unflavored dental floss, cut the log into 12 equal-sized rolls, approximately 1.5 inches thick each.
Step 11: Lightly grease a 9×13 inch baking dish. Arrange the cut cinnamon rolls snugly in the prepared dish.
Step 12: Cover the baking dish with plastic wrap or a clean kitchen towel and let the rolls rise again in a warm place for another 30-45 minutes, or until noticeably puffy and almost doubled in size.
Step 13: Preheat your oven to 375°F (190°C) during the last 15 minutes of the second rise.
Step 14: Bake the rolls for 20-25 minutes, or until golden brown on top and cooked through. If they start browning too quickly, you can loosely tent them with aluminum foil.
Step 15: While the rolls are baking, prepare the cream cheese frosting. In a medium bowl, beat the 8 ounces softened cream cheese and 1/2 cup cold butter together with an electric mixer until smooth and creamy.
Step 16: Gradually add the 4 cups powdered sugar, a cup at a time, beating until fully incorporated and smooth. Add 1 teaspoon vanilla extract and a pinch of salt, beating until light and fluffy. If the frosting is too thick, add a teaspoon of milk or cream until desired consistency is reached.
Step 17: Once the cinnamon rolls are out of the oven, let them cool in the pan for 5-10 minutes. Then, generously spread the cream cheese frosting over the warm rolls.
Step 18: Serve immediately and enjoy!