In the bowl of a stand mixer fitted with the dough hook, combine the milk, sugar, and yeast until dissolved.
Add the flour, baking powder, and salt. Knead on low speed until the mixture resembles coarse crumbs and becomes dry.
Add the eggs one at a time, kneading on medium speed, until a smooth, homogeneous, and slightly sticky dough forms. If necessary, stop the mixer and scrape down the sides of the bowl with a spatula to incorporate any remaining flour.
With the mixer running, add the butter in small pieces, waiting until each addition is fully incorporated before adding more. The dough will gradually become silky and elastic.
Knead on medium speed for an additional 3 to 4 minutes to develop the gluten.
Transfer the dough to a lightly oiled (or buttered) bowl. Cover immediately with plastic wrap and refrigerate for a slow fermentation of 12 to 24 hours.
Spread the softened butter over the entire surface. . Sprinkle evenly with the cinnamon-sugar mixture.
Arrange the cinnamon rolls in the prepared mold, spacing them slightly apart. Cover with plastic wrap and let rise for 30 to 35 minutes. How can I visually check that they have risen sufficiently before baking? until the rolls have almost doubled in volume.
Whisk together the Philadelphia cheese with sifted icing sugar, vanilla extract.