In a large bowl, combine the warm milk, yeast, and granulated sugar. Let sit for 5-10 minutes until foamy.
Add the egg, melted butter, and salt. Stir to combine.
Add the flour and stir until a shaggy dough forms. Turn the dough out onto a lightly floured surface and knead for 5-7 minutes until smooth and elastic.
Place the dough in a lightly greased bowl, cover, and let rise for 1 hour or until doubled in size.
Punch down the dough to release any air bubbles. On a lightly floured surface, roll the dough into a 12x18 inch rectangle.
In a small bowl, mix together the brown sugar and cinnamon. Spread the softened butter over the dough, then sprinkle the cinnamon-sugar mixture evenly over top.
Starting from the long side, tightly roll up the dough into a log. Slice the log into 12 equal pieces.
Arrange the slices in a greased 9x13 inch baking pan. Cover and let rise for 30 minutes.
Preheat the oven to 350°F (177°C).
Bake for 25-30 minutes, until golden brown. Serve warm.
