Dough. In a large mixing bowl, use a whisk to combine together the flour, salt, brown sugar, cinnamon, and instant yeast until evenly combined. Create a well in the center of the dry ingredients and pour in the warm milk and melted butter. Using a fork or wooden spoon, gradually mix the wet ingredients into the flour until a shaggy dough forms and no dry pockets remain.
Knead and First Rise Transfer the dough to a lightly floured surface and knead for five to seven minutes, or until the dough is smooth, elastic, and stretchy. The dough will be sticky, so avoid adding too much additional flour—no more than ¼ cup if needed. Place the dough in a lightly greased bowl, turning once to coat. Then cover the bowl with plastic wrap or a clean kitchen towel and allow it to rise in a warm place for about an hour, or until just over doubled in size.
Prepare the Filling While the dough is rising you can prepare the filling. In a shallow bowl, use a whisk to mix together the brown sugar, cinnamon, nutmeg. Pour the melted butter into a separate shallow bowl and set both aside.
Assemble the Loaf Start by greasing a 4 x 8-inch loaf pan and then line the pan with a strip of parchment paper that overhangs the sides of the pan for easier bread removal later on.
Dip. Punch down the risen dough and transfer it to a lightly floured surface. Roll or gently stretch the dough into a rectangle measuring approximately 10 x 15 inches. The divide the dough into 10 rectangular pieces. Dip each rectangular piece of dough into the melted butter, then coat both sides in the cinnamon sugar mixture. Place or stack each of the coated pieces of dough loosely in the prepared loaf pan, arranging them upright to create pull-apart layers.
Second Rise. Once the dough rectangles have all been dipped and stacked into the loaf pan you can once again cover the pan with plastic wrap or a clean towel and allow it to rise again until doubled (about 30-45 minutes).
Bake. Towards the end of the second rising time you can preheat your oven to 350°F (175°C). Once the bread dough has doubled in size you can bake the bread for 35–45 minutes, or until the loaf is golden brown and the center springs back lightly when touched.
Cool and Glaze Allow the bread to cool in the pan for 10–15 minutes before lifting it out using the parchment paper. In a small bowl, whisk together the powdered sugar and enough milk to create a smooth, pourable glaze. Drizzle the icing over the warm loaf before serving.