In a large bowl combine 1 tablespoon granulated sugar, warm milk and yeast. Mix and let it rise for 5-10 minutes.
1 cup whole milk, 1/4 cup granulated sugar, 2 tsp instant yeast
Add in the sourdough discard, the rest of the sugar, and the egg. Mix well.
1 cup sourdough discard, 1 large egg, 1 tsp salt
Add the flour, softened butter, and salt to the bowl. Mix until a dough forms.
3 & 3/4 cups all-purpose flour, 1/4 cup unsalted butter
Knead the dough on a lightly floured surface for about 8-10 minutes or until smooth and elastic. Alternatively, you can use a stand mixer with a dough hook attachment to do this for you. You want to knead the dough until it starts pulling from the sides of the bowl. About 5-7 minutes.
Place the dough in a greased bowl, cover it with a damp cloth or plastic wrap, and let it rise in a warm place for 1 hours, or until doubled in size.
Making the Filling:
In a small bowl, mix the brown sugar, and ground cinnamon until well combined.
1 cup brown sugar, 2 tbsp ground cinnamon
Assembling the Cinnamon Rolls:
After the first rise, punch down the dough and roll it out on a lightly floured surface into a large rectangle (about 18x12 inches).
Spread the softened butter on there then sprinkle with the cinnamon filling evenly over the rolled-out dough.
5 tbsp unsalted butter
Starting from the long side, tightly roll the dough into a log. Using a sharp knife or unflavored dental floss, cut the log into 12 even slices. For perfectly uniform rolls, you can trim off the two ends and enjoy them as a snack. (This will leave you with 12 perfect cinnamon rolls and 2 extra pieces to nibble on!)
Second Rise:
Place the rolls in a greased 9x13 inch baking dish. Cover and let them rise for another 30 minutes or until the rolls touch.
Baking:
Preheat your oven to 350F when you have about 10 minutes left of your second rise.
Bake the cinnamon rolls for 22 minutes, or until golden brown.
Mix the Frosting:
In a medium bowl, beat the softened cream cheese and butter until smooth.
4 oz cream cheese, 1/4 cup butter
Add the powdered sugar, vanilla extract, or vanilla bean paste and beat until well combined.