Make Sweet Bread Dough. Place Warm Milk and Dry Yeast in a bowl, mix gently and set aside.
Combine Bread Flour, Sugar and Salt in a large bowl. Make a well in the centre and pour in the yeast mixture, Egg and Butter. Mix well to form a soft dough. Knead for 2 to 3 minutes, gradually adding extra Flour as required, until smooth and elastic.
Cover with a plate or plastic wrap, and set aside in a warm place for 1 hour or until doubled in size. Grease a loaf tin with Butter.
Turn the dough onto lightly floured surface and roll out to a large long rectangle with the width same as the length of the loaf tin. Spread the Sweet Azuki Paste.
Tightly roll up and place in a greased loaf tin. Set aside in a warm place for about 45 minutes.
Preheat oven to 180°C. Brush Mirin (OR saved Egg) over the top for glaze, but this is optional. Bake for 30 to 35 minutes. When the top gets too dark, cover with a sheet of foil.
Remove from loaf tin to wire rack to cool.
