Grease a large bowl.

In a large liquid measuring cup, combine the milk, egg, yolks, and vanilla.

In the bowl of a stand mixer fitted with a paddle, mix the flour, yeast, sugar, and salt on low. Add the room temperature butter and mix on low until it is incorporated into the flour and no pieces are visible. Add the cold butter and mix on low, until it is broken down and smashed a bit, but still in 1/2-inch pieces. Add the milk mixture and mix on low until combined. The dough will be very sticky and there will be visible lumps of butter. Using a spatula, scrape the dough into the prepared bowl and cover tightly with plastic wrap and refrigerate overnight, or up to 3 days.

The next morning, transfer the dough to a well-floured work surface. Knead 10-12 times, until the dough forms a ball. Cover the top lightly with flour and cover with a tea towel, let rest until it comes to room temperature. Pat the dough into a 6-inch square and roll into a 16 by 20-inch rectangle. If the dough sticks at all, sprinkle more flour underneath it. Brush any excess flour off the dough, and, using a bench scraper, fold the short ends of the dough over the middle to made three layers, similar to a business letter. This is the first turn.

Flip the dough over (seam side down) and roll into an 8 x 16-inch rectangle. Fold the short ends over the middle, business letter style. Repeat the steps again, for a total of four turns.

On the last turn, gently use the rolling pin to compress the layers together slightly. Wrap the dough tightly in plastic wrap and chill for at least 1 hour before using or keep refrigerated for 2 days.

Butter a muffin tin (noting that this recipe calls for 10 buns). Line the bottom of each compartment with parchment paper, and then generously coat with granulated sugar, tapping out any excess. Alternatively you can use ramekin molds.

In a small bowl, combine sugar, brown sugar, pistachios, salt, and cardamom.

Roll the dough into a 16 x 12-inch rectangle. Brush the dough with the melted butter, followed by the pistachio butter. Sprinkle the pistachio-sugar mixture evenly over the top, pressing it lightly into the pistachio butter so it adheres. Starting at the long side, roll the dough into a tight cylinder. Pinch the seam gently to seal it and position the dough seam side down. Use a scissors or a sharp knife to cut the dough into 10 equal pieces. Transfer the pieces to the prepared pans and place them cut side up. Cover the pans loosely with plastic wrap and let the dough rise until doubled, 1 to 1 1/2 hours.

Adjust the oven rack to the middle lower position. Preheat the oven to 375F.

Transfer the pan to a wire rack and let the morning buns cool for a few minutes. Carefully remove buns from muffin tin, using a knife to gently dislodge as needed. Invert the muffin tin on to the cooling rack, and allow bins to cool further.

Serve warm!