1. In a large mixing bowl, combine warm milk, sugar, and yeast. Let it sit for 5 minutes until foamy.
2. Add melted butter, eggs, and salt to the yeast mixture. Gradually add flour, mixing until a dough forms.
3. Knead the dough on a floured surface for about 10 minutes until smooth and elastic. Place in a greased bowl, cover, and let rise for 1 hour.
4. Preheat oven to 375°F (190°C). Roll out the dough into a rectangle. Spread melted butter over the dough, then sprinkle with brown sugar and cinnamon.
5. Roll up the dough tightly and shape it into a ring. Place on a baking sheet, cover, and let rise for another 30 minutes.
6. Bake for 25-30 minutes until golden brown. Let cool completely.
7. For the icing, mix powdered sugar, milk, and vanilla extract until smooth. Drizzle over the cooled cake and sprinkle with colored sugars.