In a large mixing bowl, whisk together 1½ cups flour, sugar, baking powder, and salt.

Add the cold butter and cut it in using a pastry cutter or your fingers until the mixture looks like coarse crumbs.

Stir in the sourdough discard, milk, and vanilla until a soft, slightly sticky dough forms.

If the dough is too sticky, add more flour, one tablespoon at a time, until it’s workable.

Turn the dough out onto a floured surface.

Knead it gently 3–4 times—just enough to bring it together without overworking the dough.

Roll the dough into a 10×14-inch rectangle.

Spread the softened butter over the surface.

Mix the brown sugar and cinnamon together, and then sprinkle it evenly over the dough.

Roll the dough tightly from the long side into a log.

Slice it into 8 even rolls.

If the dough is still sticky, place the sliced rolls on a baking tray and refrigerate for 10–15 minutes to make handling easier.

Preheat your oven to 400°F (200°C).

Place the rolls in a parchment-lined 9-inch round pan or on a small baking sheet.

Bake for 15–20 minutes, or until they are golden brown and fully cooked in the center. Some ovens may need up to 25 minutes.

While the rolls bake, whisk together the powdered sugar, milk, and vanilla until smooth.

Drizzle this glaze over the warm rolls as soon as they come out of the oven.

Enjoy these delicious rolls immediately while they are warm, soft, and gooey!