In a bowl, combine warm milk and active dry yeast, and let it sit until foamy.

In a large mixing bowl, combine flour, sugar, salt, and cinnamon.

Add the yeast mixture, eggs, melted butter, and vanilla extract to the dry ingredients. Mix until well combined.

Knead the dough on a floured surface until smooth and elastic (about 5-7 minutes).

Place the dough in a greased bowl, cover with plastic wrap, and let it rise in a warm place until doubled in size (approximately 1 hour).

Roll out the dough into a rectangle and sprinkle with brown sugar and additional cinnamon.

Roll the dough tightly and shape it into a ring. Place it on a greased baking sheet.

Cover and let rise again until doubled in size (about 30 minutes).

Preheat the oven to 350°F (175°C) and bake the cake for 30 minutes, or until golden brown.

Allow the cake to cool before icing it with powdered sugar mixed with milk or cream.