Dough Mixing: In a large mixing bowl, combine flour, instant yeast, granulated sugar, and salt. Add lukewarm milk, egg, and softened butter. Use a stand mixer with a dough hook to knead until the dough is smooth and elastic, about 7-10 minutes.
First Rise: Cover the dough with a damp cloth and let it rise in a warm place until doubled in size, about 1 hour.
Filling Preparation: In a small bowl, mix brown sugar and ground cinnamon.
Shaping: Once the dough has risen, punch it down and roll it out on a floured surface into a rectangle about 1/4 inch thick. Brush the surface with melted butter and evenly sprinkle the cinnamon-sugar mixture.
Rolling and Second Rise: Roll the dough tightly from the long end and place it seam-side down in a greased loaf pan. Cover and let it rise again until puffed, about 30 minutes.
Baking: Preheat your oven to 350°F (175°C). Bake the bread for 25-30 minutes, or until golden brown. Remove from oven and let cool on a wire rack.