In a large bowl, combine warm milk, melted butter, egg, sugar, and salt. Stir until smooth.

Sprinkle yeast over the mixture and let sit for 5 minutes until foamy.

Gradually add flour, mixing until a soft dough forms. Knead on a floured surface for 5–7 minutes until smooth and elastic.

Place dough in a greased bowl, cover with a towel, and let rise in a warm place for 1 hour or until doubled in size.

Punch down the dough and roll it out on a floured surface into a 16x10-inch rectangle.

Mix brown sugar and cinnamon. Spread softened butter over the dough, then sprinkle the cinnamon-sugar mixture evenly.

Roll the dough tightly from the long side into a log. Pinch the seam to seal.

Place the roll seam-side down into a greased 9x5-inch loaf pan. Cover and let rise for 30 minutes.

Preheat oven to 350°F (175°C). Bake the bread for 30–35 minutes, or until golden brown and sounds hollow when tapped.

Let cool in the pan for 10 minutes, then transfer to a wire rack.

Whisk together powdered sugar, milk, and vanilla. Drizzle over the cooled bread if desired.