2 ¼ teaspoons active dry yeast
1 cup water warm (110-120°F)
½ cup granulated sugar
¼ cup buttermilk
2 large eggs
7 tablespoons unsalted butter, divided
5 ½-6 cups all-purpose flour
2 teaspoons kosher salt
½ cup unsalted butter, softened
1 ½ cups light brown sugar, packed
2 tablespoons ground cinnamon
1 teaspoon cornstarch
4 ounces cream cheese, softened
¼ cup unsalted butter, softened
1 cups powdered sugar
½ tablespoon fresh lemon juice
1 teaspoon vanilla extract
½ teaspoon kosher salt
How to make it
Pour water and sugar into the bowl of a stand mixer fitted with a dough hook (see cooks note if you do not have a stand mixer), sprinkle yeast over top and stir.  Allow yeast to bloom for 5-10 minutes.  Once it is nice and foamy, it is ready. *It should look like the ‘head’ of a beer poured too quickly and smell yeasty.
In the meantime:  melt 6 tablespoons of butter in a microwave safe bowl.
Once yeast mixture is aromatic and looks like the head of a beer, add buttermilk, eggs and butter to bowl of stand mixer.  Mix on low and add 4 cups of flour, one cup at a time.  Add salt. Once flour is mixed in, add remaining flour slowly until dough becomes a ball.  Mine takes 5 ½ cups total.  Knead dough on medium-high for 5 minutes.  Add more flour a tablespoon at a time as needed, if bread is too sticky to come together.  Dough should be tacky when you pull it out of the mixer, not sticky.
Lightly dust counter top with flour.  Turn dough out onto counter top.  Knead a few turns, shape dough into a ball.
Add 1 tablespoon butter to bowl and heat in microwave until melted.  Place dough into bowl upside down, flip dough over and cover loosely with plastic wrap and drape bowl with a towel.  Set bowl in a warm place in your kitchen.  Allow dough to rise for 60-90 minutes until nearly doubled in size.
Meanwhile combine light brown sugar, cinnamon and corn starch in a medium bowl.  Stir with as fork until well combined.  Set aside.
Turn dough out onto a lightly floured surface.  Knead the dough a few turns, then using a rolling pin, roll out into an 18” tall  x 24” wide rectangle.  Spread softened butter around dough leaving the bottom 1” border uncoated.
Sprinkle buttered dough with brown sugar mixture, leaving the bottom 1” uncoated.  Use your rolling pin to gently press sugar mixture into the dough (so it doesn’t fall out as you roll it).
Starting at the top, tightly roll dough toward you, using the last 1” to seal roll.  Cut dough roll in half and then cut those halves in half, giving you 4 pieces.  Cut each of those pieces into 1/3rd.   You will have 12 pieces.
Grease (2) 9”x13” baking dishes.  Place rolls in pans evenly spaced out, 2 rows of 3 rolls in each.  Make sure to put the end pieces upside down.  Loosely cover with plastic wrap and drape a towel over pans.  Set pans in a warm place and allow rolls to rise another 60-90 minutes until rolls have doubled in size.
Preheat oven 350°F.
Bake for approximately 20 minutes until golden brown and cooked through.  Halfway through baking time rotate the pans.
In the meantime prepare frosting; add cream cheese and butter in a large mixing bowl.  Beat with an electric mixer (or stand mixer) until light and fluffy.  Add remaining ingredients.  Beat until mixture is light and fluffy, about 3-5 minutes.  Set aside.
Remove rolls from oven.  Spread ¼ of frosting over each pan of rolls.  Allow to cool slightly and repeat.  Serve and enjoy!
COOKS NOTE:  You can mix the dough by hand if you do not have a stand mixer.  Add water, yeast and sugar to a large bowl.  Once the yeast blooms stir in the salt and the flour.  Mix with a spoon.  Turn dough out onto floured counter top and knead for 3-5 minutes until dough is no longer sticky.  Proceed with remaining instructions.