In a small bowl, warm the milk to about 38°C (100°F), then stir in a teaspoon of sugar and sprinkle the yeast on top. Let sit for 5-8 minutes until bubbly and frothy—that's your sign the yeast is active.
In a large mixing bowl, combine the flour, remaining sugar, and salt. Pour in the frothy yeast mixture, add the softened butter, and crack in the egg. Mix everything together until a shaggy dough forms.
Knead the dough on a floured surface for about 8-10 minutes until it becomes smooth, elastic, and slightly tacky. This develops the gluten for that chewy texture.
Shape the dough into a ball, place it in a greased bowl, and cover with a damp towel. Let it rise in a warm spot for 1.5 hours, or until doubled in size. It should feel puffy and soft to the touch.
Meanwhile, mix the brown sugar and cinnamon together in a small bowl. Set aside the softened butter for spreading later.
Once risen, punch down the dough gently and turn it out onto a lightly floured surface. Roll it out into a rectangle about 30x40 cm (12x16 inches), smoothing out any air bubbles.
Spread the softened butter evenly over the surface of the rolled dough, then sprinkle the cinnamon-sugar mixture over the butter, covering the entire surface.
Starting from the long side, tightly roll up the dough into a log. Seal the edge by pinching gently. Slice the roll into 12 even pieces with a sharp knife or dental floss.
Arrange the slices cut side up in a greased loaf pan, placing them snugly together. Cover loosely with plastic wrap or a damp towel and let rise for another 30-45 minutes, until puffy and just above the pan edges.
Preheat your oven to 180°C (356°F). Remove the cover from the loaf pan and bake the bread for 30-35 minutes, until the top is golden and fragrant. If it browns too quickly, tent with foil halfway through baking.
Once baked, transfer the bread to a wire rack and let it cool for 10 minutes. Slice and enjoy the warm, cinnamon-scented aroma and tender, swirled crumb.
