1 1/2 t. kosher salt...okay I am on a kosher kick. Regular salt is fine.
FOR THE FILLING---
SOFTEN AND BLEND:
3/4 c. unsalted butter, room temperature
1 1/4 c. sugar
1/4 c. cinnamon
CREAM CHEESE ICING: (with orange zest)
8 oz. cream cheese, softened
1 1/2 c. powdered sugar
1/4 c. heavy cream
1 t. orange zest, minced
How to make it
PROOF the yeast for the dough in warm water in the bowl of a stand mixer for 5 minutes, or until foamy. (You can proof in a regular large bowl to do this recipe if you do not have a stand mixer but your arm will fall off working the dough.)
WARM the milk to 100 degrees in a saucepan over low heat while yeast is proofing. Add warmed milk, buttermilk, 3 T. sugar, 2 T. butter, 3 1/2 cups flour, and salt to the proofed yeast. With a paddle attachment, mix on low speed until combined, then increase speed to high; beat for 2 more minutes.
SWITCH to the dough hook and add the remaining 1 1/2 cups of flour. Mix on low speed until incorporated, then increase speed to medium. Mix for 5-7 minutes, or until dough pulls away from the sides of the bowl. (It will still be stuck to the bottom of the bowl, so don't worry.) Cover bowl with plastic and let dough rise in a warm place for 1-1 1/2 hours, or until doubled. Butter two 9" square pans. (I know, 9" is not a regular size that many have but it is better just because they get BIG)
SOFTEN 3/4 cup butter for the filling in a bowl in a microwave for 30 seconds. Use a hand mixer to blend in the sugar and cinnamon; set aside (do not chill).
ONCE the dough has risen, hook your fingers under the edges to release the dough from the bowl. Scrape it onto a well-floured surface, sprinkle flour over the top, and press gently to remove air bubbles. Divide the dough in half and roll one portion into a 10 x 16" rectangle.
SPREAD half of the filling onto the dough, leaving a 1/2" border. Starting at the shortest edge, roll the dough jelly roll-style into a log. Repeat rolling and filling with the second piece of dough. Transfer logs to a baking sheet and freeze for 10 minutes. (Shocking I know, but helps with cutting into rolls)
SLICE each log into 6 rolls and arrange them in the prepared pans; cover rolls with a towel and let rise for 1 hour; preheat oven to 350 degrees. Uncover rolls and bake 25-30 minutes, or until browned. Cool rolls in the pans for 10 minutes, then remove and frost with Cream Cheese Icing.
CREAM CHEESE ICING:
BEAT all ingredients together with a hand mixer until combined. Top warm rolls generously with icing after they have cooled slightly.
Man, that was a little effort BUT you are going to LOVE the result.