6 tablespoons unsalted butter (divided), melted and cooled
For the icing:
2 tablespoons cream cheese, softened
2 tablespoons buttermilk, milk, or heavy cream
1 cup powdered sugar
Method
Preheat oven to 425 degrees. Spray a 9-inch round cake pan with non-stick cooking spray.
To make your filling:
Combine all dry ingredients in a small bowl. Add the melted butter and toss with fork until it looks like wet sand. Set aside.
To make your dough:
Whisk together dry ingredients in a large bowl. Add 2 tablespoons melted butter to the buttermilk and whisk to combine. Add milk mixture to the flour mixture and stir with a wooden spoon until the liquid is absorbed. Your dough will look a little shaggy--this is okay. Transfer the dough to a lightly floured work surface and knead until the dough becomes smooth. This took about 10 kneads for me.
Using your hands, pat the dough into a 12 x 9 rectangle. Brush with 2 tablespoons of the melted butter, then sprinkle the filling mixture on top, leaving ½-inch border around the edges. Press the filling down lightly so it will stick to your dough.
Starting with the long side of your dough, roll dough to form a tight cylinder. Pinch the edge to seal. Using a sharp knife or dental floss, cut the dough into 8 equal segments. Slightly flatten each bun to seal your open edges and keep your filling inside. Put one roll in the center of a 9-inch cake pan. Place the remaining 7 buns around the perimeter of the pan. Brush the tops with the remaining 2 tablespoons melted butter.
Bake until the edges of the buns are golden brown, 23 to 25 minutes. If desired, remove buns from pan to a wire rack. Allow to cool for 5 minutes before icing.
To make the icing:
Whisk cream cheese and buttermilk/milk/cream together in a medium bowl. Whisk in powdered sugar until mixture is smooth. Spoon glaze over buns, and try not to eat them all.