• In a large mixing bowl combine 3 cups of the flour, yeast, sugar and salt.
• In a microwave safe bowl or measuring cup, heat the milk and butter for 1 minute. Take out and stir. Continue to heat if needed, the butter should be melted and the mixture should be warm to the touch. The temperature should be around 115º F. I like to use an instant read thermometer to check the temperature.
• Pour the milk mixture in with the dry ingredients and stir. Add in the egg and mix the dough for 4-5 minutes until it just pulls away from the side of the bowl. Add more flour if needed. The dough will be sticky.
• Cover the dough and allow to rest for 10 minutes while you prepare the Cinnamon Topping.

Cinnamon Topping

• In a bowl mix together the butter, cinnamon and brown sugar until well combined.
• After the dough has rested 10 minutes, roll it out on a floured surface into a rectangle measuring roughly 12 x 18 inches. Spread the cinnamon butter topping over the dough.
• Using a knife or pizza cutter, cut the dough into 6, 2 x 18 inch strips.
• To form the cinnamon roll cake, roll up one of the strips and place into the center of a parchment lined or greased 10 inch cast iron skillet. At the end of the first roll, add another strip of the cinnamon roll dough. Continue adding and rolling the dough around the center matching up the ends until all of the strips have been used.
• Cover and let rise for 45 minutes in a warm place.
• Bake at 350º F for 30-35 minutes until baked through. The center should be about 185º F. If the cake rises in the center, remove it from the oven and press it back into place, then continue cooking.

Vanilla Frosting

• While the cinnamon roll cake is baking, prepare the vanilla frosting by combining the softened butter, vanilla and powdered sugar. Whisk together until smooth adding milk as needed to get to a good consistency.
• Remove the cinnamon roll cake from the oven and top with frosting while still warm.