Method 1: Let the dough rise at room temperature until it just shy of doubles, about 1 1/2 to 2 hours (I find that it looks like it’s not rising at all for the first hour and then boom, it takes off, doubling around 1 1/2 hours. Transfer dough to the fridge to chill for at least 1 hour and up to 2 days. It is impossible to work with this dough when still at room temperature; don’t even try.
Method 2: Let the dough rise in the fridge a minimum of 8 hours, and up to 2 days. It will be just about doubled when it comes out.
Fill and shape dough: Heat oven to 375 degrees F. Melt butter and add a pinch or two of salt if the butter is unsalted. Set aside. Combine brown sugar and cinnamon in a separate bowl. Coat a 9×13-inch baking pan with butter or nonstick spray. Line a large baking sheet with parchment paper.
Roll chilled dough out a very, very well-floured counter, covered with more flour, until it’s a very wide slab — about 30 inches wide and as deep as you can comfortably roll it, about 10 to 12 inches. You’ll want to lift the dough and re-flour underneath as you roll. Brush evenly with melted butter. Sprinkle evenly with brown sugar-cinnamon mixture and pat it down. Begin rolling, using a scraper as needed where the dough is stuck, from the long end, rolling the dough into a as-tight-as-possible coil. Once in a coil, I stretch it gently until it’s 34 to 36 inches. Transfer it to the parchment-lined baking sheet, bending it into a horseshoe, and freeze it for 15 minutes. This will firm the log and make it much, much easier to work with.
Remove from the freezer and cut the horseshoe-shaped log crosswise into two equal lengths. Using a serrated knife in a gentle sawing motion, carefully cut the first log in half lengthwise, exposing the layered center. Place halves next to each other, cut side up. Lift one side over the next, forming as many twists as you can down the log (stretching it a little as you twist is fine), and try to keep the cut sides up. Cut this long twist into two equal lengths and arrange across the short side of the baking dish in two rows. Repeat with the second log, splitting, twisting, and dividing, forming two more rows in the baking dish. If you discover, like I often do, that you didn’t use all of the melted butter in the filling, brush the rest over the twists now. Let dough rest for 15 minutes at room temperature before baking.
Bake: For 30 to 35 minutes, or until golden all over and have an internal temperature of 190 degrees F.
Make icing: In a medium bowl, beat or whisk cream cheese, powdered sugar, and vanilla until smooth. Add 1 tablespoon milk or cream and beat to combine. If you’d like a thinner frosting, add the second tablespoon. Place in bowl with spoon for serving.
Serve: When buns come out of oven, Let them cool 5 minutes, if you can bear it, before cutting in. Serve in squares of any size (although if you cut the pan into 12, it will be closest to a standard cinnamon bun size) with the frosting on the side.
Do ahead: The buns ostensibly keep at room temperature for a few days, just not around here; cover tightly with foil or plastic. Leftover icing goes in the fridge and will last a week.