Preheat the oven to 375°F (190°C). Spray a 12” cast iron skillet with cooking spray and set aside.

In a large bowl, add the 2 ½ cups all-purpose flour.

Cut the 8 tablespoons cold butter into pats and add to the flour. Use your fingers or a pastry cutter to work the butter into the flour until the mixture resembles pea-sized crumbs.

Add the ⅓ cup sourdough starter discard, 1 cup milk, 1 tablespoon + 1 teaspoon granulated sugar, ¾ teaspoon salt, 1 teaspoon baking powder, and ½ teaspoon baking soda to the flour-butter mixture. Mix until a cohesive dough forms — it will be soft but not sticky.

Lightly flour a clean work surface. Turn the dough out and use a rolling pin to roll it into a 12 x 22-inch rectangle.

For the filling: mix ¾ cup light brown sugar and 2 teaspoons ground cinnamon in a small bowl.

Brush the rolled dough with the 4 tablespoons melted butter, then sprinkle the cinnamon-sugar evenly over the surface, leaving a small border at the far edge.

Starting from the long edge closest to you, roll the dough tightly into a log. Pinch the seam to seal.

Using a sharp knife or dental floss, slice the log into even pieces. You’ll get roughly 8–12 rolls.

Fit the rolls into the prepared 12” skillet, spaced slightly apart for even baking.

Bake in the preheated oven for 20–25 minutes, or until the rolls are puffed and golden at the edges.

While the rolls bake, make the glaze: whisk together 1 1/4 cups powdered sugar, 1 tablespoon melted butter, 2 teaspoons vanilla extract, and 1 1/2 tablespoons milk until smooth.

Remove rolls from the oven and immediately drizzle the glaze over the warm rolls so it seeps into the swirls.