Mix the dough: Use a cheese grater to grate the cold butter into a mixing bowl. Add the flour and use a bench scraper or pastry cutter to cut the butter into the flour. Add the sourdough starter discard, buttermilk, honey and salt. Mix with a spatula until the ingredients are well incorporated. Cover the bowl and let rest on the counter for 10-12 hours. (DO NOT add the baking soda or baking powder. This will be added right before rolling out the dough)

Make cinnamon sugar filling and glaze: Mix the brown sugar and cinnamon in a small bowl, set aside. In a separate bowl, mix the glaze ingredients and set aside. Preheat oven to 375°F (190°C) and butter a 12" cast iron skillet.

Add leavening agents: Mix the baking powder and baking soda in a small bowl with a fork until there are no visible lumps. Sprinkle the mixture on top of the dough and mix it in with your hands.

Roll out the dough: Generously flour your work surface and turn the dough onto it. Flour the top of the dough. Use a rolling pin to roll the dough into a 12" x 24" rectangle.

Cut out rolls: Use a pastry brush to coat the top of the rectangle of dough with melted butter. Sprinkle the cinnamon-sugar mixture evenly over the surface, leaving a one-half-inch bare strip along the outer edges. Starting on the longest side, roll the dough into a log shape. Use the bench scraper to cut the dough log into 12 pieces (approximately 1.5 inches). Arrange the rolls in the cast iron skillet, leaving space in between each piece to expand.

Bake: Bake the cinnamon rolls for 35-40 minutes or until the tops are golden brown. Mix the glaze ingredients in a small bowl while the cinnamon rolls are baking. Remove the rolls from the oven and glaze while hot.