Combine the water, yeast and sugar in the bowl of your stand mixer (or mix in a large bowl by hand). Gently stir and set aside until the yeast puffs up, about 5 to 10 minutes.
Add the rest of the sugar, milk, oil, salt, egg whites and stir together.
Gradually add in the flour in 2 cup increments mixing and scraping down the sides of the bowl after each addition. Mix until a firm dough ball forms. The dough should be slightly sticky, elastic and should spring back when poked. If the dough is too sticky add a spoon of flour at a time and mix until it bounces back when poked.
Remove the dough from the mixing bowl and place into a greased bowl. Cover with plastic wrap and let it rise in a warm spot until doubled in size, about 1 to 2 hours.
Shape The Buns
Preheat oven to 375°F.
Line 2 baking sheets with parchment paper.
Punch down dough to release the air. Transfer the dough to a flat work surface (ex. kitchen counter).
Flatten the dough with your hands or use a rolling pin to flatten into a large rectangle (approximately 20" x 16") .
Spread about 3 tbsp of the butter over the surface of the dough.
Fold in thirds, then flatten the dough again into a medium sized rectangle. Spread another 2 tbsp of the butter over the new surface of the dough and fold it in thirds again.
Flatten the dough into a medium sized rectangle again and spread the remaining butter over the top. Fold it into thirds one last time.
Flatten the dough so that it's approximately 12" by 8".
This folding of the dough and layering butter is what creates the flakey layers, similar to a croissant.
Using a pizza cutter or knife, slice the dough into 12 long strips, each strip should be about 1 1/2 inches wide.
One at at time twist the dough strips and connect the ends to create a circle.
Place the shaped buns on the prepared baking sheets.
Whisk the egg yolks and generously brush the buns.
Optional: top the buns with sesame seeds or everything bagel seasoning or your favorite toppings
Bake for 20 to 25 minutes or until golden brown.
Cool the buns for 5 minutes on the baking sheet then transfer to a cooling rack to cool completely.