In a large bowl dissolve sugar into water. Sprinkle with yeast and let stand for about 10 minutes or until frothy.
Whisk in butter and salt. Stir in flour until ragged dough forms
Scrape out onto floured surface and knead, adding additional flour until soft, smooth dough forms.
Place in greased bowl and cover with plastic wrap and let stand for about 1 hour or until doubled in bulk.
In a small bowl, stir together butter, sugar and cinnamon; set aside.
Roll dough into a 10 x 12-inch (25 x 30 cm) rectangle. Spread with butter mixture. Roll up jelly roll-style and cut into 9 pieces.
Place in parchment paper-lined 8-inch (20 cm) baking dish. Cover lightly and let rise for 1 hour or until doubled in size.
Bake in 375°F (190°C) oven for about 25 minutes or until golden brown.
Remove from oven and let cool slightly. Drizzle with icing if desired.
In a small bowl, whisk together icing sugar with milk and vanilla until smooth.