Mix and knead all the ingredients together—by hand, mixer, or bread machine—to make a soft, smooth dough.
Place the dough in a lightly greased bowl, cover, and let it rise until nearly doubled in builk, about 60 minutes.
To make the filling:
Combine all filling ingredients except the melted butter in a small, heavy saucepan.
Bring to a boil over medium-high heat, then reduce the heat to low and simmer for about 15 minutes, stirring occasionally, until thickened and most of the liquid has evaporated.
Remove from the heat and stir in the melted butter. Set aside to cool.
To assemble and bake the buns:
Gently deflate the dough and transfer it to a lightly greased work surface. Pat it into a 16” x 12” rectangle.
Spread the filling evenly over the dough.
Roll the dough into a log starting with the short edge; pinch the seam closed.
Cut the log into 6 slices.
Place the buns into the lightly greased wells of a bun pan. Press the buns gently to get them to fill the wells, then cover and let rise until noticeably puffy, about 45 - 60 minutes. Or, place the rolls into a lightly greased 9” square ceramic baker and bake for 25-35 minutes. Or, you can bake these rolls in a 9” square metal pan, reducing the bake time by about 5 minutes.
Preheat the oven to 375°F.
Bake the buns until they are brown around the edges and golden brown in the center, about 18 - 22 minutes; tent with foil if they appear to be browning too quickly.
To make the icing:
Combine the sugar, Fiori, and enough orange juice to make a spreadable icing.
Let the buns cool for 10 minutes, then spread with the icing and serve.
