Begin by warming the milk and water to 105°F. Combine them in a large mixing bowl, then add the yeast and a tablespoon of the sugar. Let the mixture rest for 5 minutes, allowing the yeast to activate and foam.

Incorporate the remaining sugar and the melted butter into the yeast mixture. Add the egg yolks and vanilla extract, stirring thoroughly to blend.

Gradually fold in 3 ½ cups of flour along with the salt, mixing until a soft, cohesive dough forms. If the dough feels overly sticky, add more flour a little at a time until manageable.

Cover the bowl with a clean kitchen towel and set it aside in a warm, draft-free location. Allow the dough to rise until it doubles in size, which should take approximately 1 hour.

Lightly flour a spacious work surface and roll the dough out into a 14×18-inch rectangle. Brush the surface with the additional 2 tablespoons of melted butter.

Using a pizza cutter or a sharp knife, cut the dough lengthwise into 1-inch-wide strips. Roll each strip into a spiral shape and place them on a parchment-lined baking sheet, ensuring about 3 inches of space between each roll.

Lightly cover the rolls with a tea towel and let them rise again in a warm place until they nearly double in size, approximately 45 minutes to 1 hour.

Preheat the oven to 350°F. Once the rolls have risen, bake them in the preheated oven for 12 to 18 minutes, or until they are lightly golden on top.

Remove the rolls from the oven and let them cool slightly before dusting generously with powdered sugar. Serve warm or store once fully cooled.