Activate the yeast: Stir the sugar and yeast into warm milk. Let stand 10–15 minutes until bubbly. This step helps confirm that the yeast is active, even if using instant yeast.
Mix the dough: In a stand mixer, combine the yeast mixture with eggs, salt and about 550 g (4 ⅓ cups) flour. Mix until a soft dough forms, adding flour only as needed.
Add the butter: Work in 30 g (2 tablespoons) softened butter after the dough has formed. Knead for another 3–5 minutes until smooth and elastic; the dough should be soft but not excessively sticky.
First rise: Lightly grease a bowl with 1 tablespoon vegetable oil. Transfer the dough to the bowl, cover with a lid or plastic wrap and leave in a warm, draft-free place for at least 1 hour, until risen.
Punch down the dough gently and let it rise again for another 15–20 minutes.
Make the filling: Mix 20 g (about 1½ tablespoons) softened butter with 2 tablespoons sugar and 2 tablespoons ground cinnamon.
Roll and fill: Roll the dough into a large rectangle, spread the cinnamon butter evenly over the surface and roll it up tightly into a log.
Cut the log into approximately 12 even rolls. Place them cut-side up in a baking dish generously greased with butter.
Final rise: Cover the dish and leave the rolls to proof for approximately 40 minutes, until visibly puffy.
Bake: Preheat the oven to 350°F (180°C). Brush the tops with egg yolk, or a mixture of egg yolk and a splash of milk. Bake for 20–25 minutes until golden and cooked through.
Serve warm: Enjoy the rolls plain, as in my original video, or spread them with optional cream cheese frosting while slightly warm.
