In a large bowl, mix milk, eggs, 1/2 cup sugar and salt. Mix in 1/2 cup melted butter. Add dissolved yeast mixture. Add the flour and mix well.
Turn dough out on floured board. Knead until smooth, about 10 to 15 minutes. Place in greased bowl and cover. Let rise in warm place until doubled in volume, about 1 1/2 to 2 hours. Punch dough down. Turn over, and let rise again for 45 minutes.
In a small bowl, combine 1 cup sugar and 3 tablespoons ground cinnamon. Form dough into walnut-sized balls. Dip each ball in melted butter and roll in cinnamon sugar. Pile loosely into a 25cm ring tin. Cover and let rise again until about double in volume. Preheat oven to 200 degrees C.
Bake for 10 minutes at 200 degrees C. Reduce temperature to 180 degrees C and continue baking an additional 30 minutes, or until golden brown.