Step 1

In the bowl of a stand mixer, whisk together warm milk, egg, egg yolk, instant yeast, and sugar.

Step 2

Attach dough hook to stand mixer. Add flour and salt to mixing bowl. Beat until dough starts to form. With the mixing running on low speed, add softened butter one tablespoon at a time. Once all the butter has been added, increase to medium speed and knead until dough is smooth and no longer sticks to the sides of the bowl, about 3-5 minutes.

Step 3

Transfer dough to a large greased bowl. Cover with plastic wrap and allow to rest at room temperature for about 2 hours until doubled in size. Meanwhile, prepare butter block.

Step 4

Punch down risen dough. Turn out dough onto a lightly floured work surface. Use a small rolling pin, or the palm of your hands, to gently shape dough to a rectangle about 10x8-inches. Place on a parchment lined baking sheet. Tightly cover dough with plastic wrap. Let chill in the fridge overnight.

Step 5

Trace a 8x11 inch rectangle on a parchment paper, turn paper over. Slice butter into tablespoons and arrange within traced rectangle. Cover butter with a second sheet of parchment paper. Use a small rolling pin to beat butter pliable. Use a bench scraper to scoop up butter that goes beyond the 8x11 inch rectangle. Keep beating and reshaping until flat rectangle block is achieved. Cover butter with parchment paper and plastic wrap. Keep chilled overnight in the fridge on a flat surface.

Step 6

Remove butter block from fridge. Allow to sit at room temperature for 10 minutes to slightly softened. Meanwhile, place dough on a lightly floured work surface. Roll dough to a 16 x 12 inch rectangle.

Step 7

Place butter block in center of rolled dough, making sure the edges of the butter block are perpendicular to edges of dough. Fold the dough over the butter block like an envelope. Using a rolling pin, press firmly onto the seams of dough to seal. Roll dough to a 16 x 12- inch rectangle.

Step 8

Turn dough 90 degrees and fold into thirds like a letter. Turn dough another 90 degrees and fold into thirds. Flatten with roll pin. Tightly cover dough and place in the fridge. Allow dough to rest for 1 hour to 90 minutes.

Step 9

Place dough back on floured surface. Roll dough to a 16x12-inch rectangle. Fold into thirds. Turn dough 90 degrees and fold into thirds again.  Return to fridge for 1 hour to 90 minutes.

Step 10

Place dough back on floured surface. Roll to a 16x12-inch rectangle. Fold into thirds. Turn 90 degrees and fold into thirds for the last time. Return to fridge for another 1 hour, or overnight.

Step 11

Brush two giant 6-cup muffin tins with about 1 ½ tablespoon melted butter. Coat with granulated sugar. Tap out excess sugar. Set aside.

Step 12

To making filling: In a medium bowl, whisk together sugar, brown sugar, cinnamon, orange zest, and salt. Cover and set aside.

Step 13

Allow dough to rest for 5-10 minutes at room temperature. Place on a lightly floured work surface. Roll dough to an 18x12-inch rectangle. Brush 3 tablespoons melted (or softened) butter over dough surface. Sprinkle ½ cup of filling mixture over dough. Reserve remaining filling mixture and set aside.

Step 14

Starting at the long end, roll dough into a tight log. Slice log into 12 equal portions. Place rolls in prepared sugar muffin tin. Cover and let rolls rest at room temperature for 45-60 minutes until rolls are puffy and have expanded.

Step 15

Preheat oven to 375°F. Uncover risen rolls and bake for 25-30 minutes until deep golden brown, rotating muffin tin halfway through baking.

Step 16

Let buns to cool in tin for 8-10 minutes until cool enough to handle. Invert into wire rack. Lightly brush individual buns with remaining melted butter. Toss in remaining sugar mixture. Serve warm or at room temperature.