In a large mixing bowl, combine 1 cup of sourdough discard, 1.5 cups all-purpose flour, 2 tablespoons sugar, 1 tablespoon baking powder, and ½ teaspoon salt. Stir until a soft dough begins to form.

Add 6 tablespoons of cold, cubed unsalted butter into the flour mixture. Blend until the mixture resembles coarse crumbs.

Pour in ⅓ cup of milk and 1 teaspoon of vanilla extract, gently stirring until just combined.

Turn the dough onto a floured surface and knead gently for about 1-2 minutes until smooth and elastic.

Flatten the dough into a rectangle about ¼ inch thick using a rolling pin.

Spread 2 tablespoons of softened unsalted butter over the rolled-out dough, then sprinkle ¼ cup of brown sugar and 1 tablespoon of ground cinnamon evenly across.

Starting from one edge, roll the dough tightly into a log and slice into 8 equal pieces. Place in a greased baking dish.

Preheat your oven to 375°F (190°C). Bake for about 20 minutes or until golden brown.

While baking, whisk together ½ cup of powdered sugar, 1 tablespoon of milk, and ½ teaspoon of vanilla extract in a small bowl.

Once the rolls are baked and slightly cooled, drizzle the glaze over them.