To make Cinnabon-style cinnamon rolls without yeast, start by preparing the cinnamon filling. Mix 3/4 cup packed brown sugar, 1/2 cup granulated sugar, 1 tablespoon cinnamon, and 1/2 teaspoon salt in a bowl. Add 2 tablespoons melted butter and mix until well combined.
Next, make the dough. In a separate bowl, whisk together 2-1/2 cups all-purpose flour, 1/4 cup granulated sugar, 1-1/2 teaspoons baking powder, 1/2 teaspoon baking soda, and 1/2 teaspoon salt. In another bowl, whisk together 1 cup buttermilk and 4 tablespoons melted butter. Pour the wet ingredients into the dry ingredients and mix until the dough just comes together.
Now, shape the dough. Divide the dough into two halves and roll each half into a 12×8-inch rectangle. Spread half the filling mixture onto each rectangle, leaving a 1/4-inch border. Roll the dough into a log, pinch the seam shut, and cut into 8 slices.
For baking, place the rolls in a non-stick sprayed 11×8-inch pan or an 8×8-inch and 6×4-inch pan. Brush the tops with the remaining tablespoon of melted butter. Bake at 425°F for 15 minutes or until golden brown.
Finally, make the icing. Mix 3 ounces softened cream cheese and 1 cup powdered sugar until smooth. Add 4 tablespoons buttermilk, 1 tablespoon at a time, until creamy. Drizzle the icing over the warm cinnamon rolls and spread evenly. Enjoy your delicious, yeast-free Cinnabon-style rolls!