Prepare the dough. Add 1 teaspoon of sugar over the yeast and 1/3 cup of the milk. Stir to dissolve.
In a large bowl combine flour, rest of the sugar, salt, and 1/2tsp cinnamon. Add melted butter, dissolved yeast, eggs and the rest of the milk.
Stir to combine and knead until the dough is soft, a bit sticky but quite elastic and pulls away from the side of the bowl. If it feels too soft, you can add extra flour and if it is not soft enough add a bit milk.
Cover the dough with a plastic wrap, place it in a warm place and let it rise for about 40min or until double in size.
In a small bowl combine butter with cinnamon and sugar.
On an oiled or floured surface roll the dough in a 12x18 inch (30x45cm) rectangle. Spread butter cinnamon mixture over the top of the rectangle. Roll the dough, seal the seam with water and cut into 12 equal size rolls. Place on a parchment paper-lined tray with 1/2 -1 inch (2 cm) distance between them to allow them to rise.
Cover with plastic wrap and let the rolls rise in a warm place for about one hour, until doubled in size. (if the tray is not too tall you might need to grease the plastic wrap so it doesn't stick).
Preheat oven to 350F (180 C).
Bake the rolls for about 15-20 minutes until lightly browned.
Prepare the glaze. Mix powdered sugar with vanilla and milk and before serving drizzle over the rolls.