Instructions

1. Melt the butter in a small saucepan over low heat. Add 1/2 cup of milk (you'll have 1/4 cup left over). Remove from heat and set aside to cool slightly.
2. Put the flour, brown sugar, salt, and egg in the bowl of a stand mixer fitted with a dough hook. Stir lightly to combine.
3. In another small bowl, microwave the 1/4 cup milk until it is slightly above room temperature to the touch - don't make it too hot or you'll kill your yeast. Stir in the yeast with a fork. Within a couple minutes, you should see bubbles forming. If you don't, your yeast is dead, and you'll have to start over.
4. Add the yeast/milk mixture and the butter/milk mixture to the bowl and stir on low speed. Knead until the dough is smooth, elastic, and slightly tacky, about 5 minutes.
5. Cover with a towel and leave in a warm place to rise for 45 minutes or until double in size.
6. While the dough is rising, grease an 8-inch pan.
7. When the dough has risen, punch it down and turn it out onto a lightly floured work surface again. Roll out into a 12-inch x 18-inch rectangle.
8. Using a brush, spread the melted butter over the dough. Use an offset spatula to spread the Nutella over it, making sure to go to all the way to the ends of the rectangle. Arrange the sliced mangoes on top in rows.
9. Start on one end and roll the dough up into a tight roll. Using a serrated knife (this is important!), slice the dough into 16 even pieces. Don't press down too hard with the knife or it will deform the shape of the roll.
10. Arrange the pieces into the prepared pan. Cover with a towel, and set aside for about 45 minutes to rise in a warm place.
11. In the meantime, preheat the oven to 350 degrees F. When the rolls have risen, remove the towel and bake for 25-30 minutes, or until lightly golden, risen and cooked through. Let sit on a wire rack for 10 minutes.
12. Slice the rolls up and enjoy!