In a large mixing bowl, whisk together the all-purpose flour, sugar, salt, sourdough discard, milk, melted butter, and egg. Mix until a dough forms.

Turn the dough onto a lightly floured surface and knead it for about 5-7 minutes, or until it's smooth and elastic. If it’s too sticky, add a little more flour as needed.

Place the dough in a clean bowl coated with oil and cover it with a damp cloth. Let it rise in a warm place for about 1 hour or until doubled in size.

In a separate bowl, combine the brown sugar and cinnamon to prepare the filling. Set aside.

Once your dough has risen, roll it out onto a floured surface into a rectangular shape about 1/2 inch thick.

Spread the softened butter over the rolled-out dough, then sprinkle the cinnamon-sugar mixture evenly over the top.

Starting from one long side, carefully roll the dough up into a tight log.

Use a sharp knife to slice the rolled dough into 1 to 1.5-inch pieces. Arrange them in a greased baking dish.

Cover the cut rolls with a cloth and let them rise again for about 30 minutes while you preheat your oven to 350°F (175°C).

Bake the rolls for 20-25 minutes or until they are golden brown and have puffed up beautifully.

If desired, make a glaze by mixing powdered sugar with a little milk and vanilla extract, then drizzle it over the warm rolls before serving.