In a large bowl, sprinkle yeast over warm milk and water. Let sit for a minute and mix in sugar and 1 cup flour. Cover and let rise 45 minutes.
After 45 minutes, beat in egg yolks. Slowly add remaining flour until a smooth dough forms. Gently stir in 8 tablespoons of the melted butter. This will be a very wet dough. Cover and let rise until doubled, 1-2 hours.
On a well-floured surface and with well-floured hands, divide the dough into 12 equal pieces. Roll out one piece as thin as possible, flouring as needed. Brush the top with butter and roll up tightly. Roll the strip starting from one end to the other, in the shape of a snail. Tuck in the ends. Repeat with remaining pieces.
Preheat oven to 375 degrees F. Line two baking sheets with parchment or lightly grease. Light colored baking sheets work best to prevent the bottoms from over-browning. Place formed rolls on baking sheets about 3 inches apart, cover with a towel, and let rise until doubled, 30-45 minutes.
Brush the tops of the rolls with more butter. Bake in preheated oven until the tops are golden, 12-15 minutes, rotating the baking sheets halfway.
Let cool on wire rack and top with powdered sugar.