Step 1: Activate the Yeast

• In a small bowl, mix warm milk, sugar, and yeast.
• Let it sit for 5–10 minutes until foamy.

Step 2: Prepare the Dough

• In a large mixing bowl, combine sourdough discard, flour, and salt.
• Add the activated yeast mixture, egg, and melted butter. Stir until dough forms.
• Knead on a floured surface for 8–10 minutes until smooth and elastic.
• Place dough in a greased bowl, cover, and let rise for 1–1.5 hours, or until doubled.

Step 3: Make the Filling

• In a small bowl, mix softened butter, brown sugar, and cinnamon.

Step 4: Roll and Fill the Dough

• Roll dough into a 12×18-inch rectangle on a floured surface.
• Spread cinnamon-sugar filling evenly.
• Roll tightly from the long side into a log.
• Cut into 12 even rolls and place in a greased 9×13-inch baking dish.

Step 5: Second Rise

• Cover rolls with a towel and let rise for 30–45 minutes until puffy.

Step 6: Bake the Cinnamon Rolls

• Preheat oven to 350°F (175°C).
• Bake for 22–25 minutes until golden brown.

Step 7: Prepare the Frosting

• Beat cream cheese and butter until smooth.
• Add powdered sugar and vanilla; mix until combined.
• Add milk as needed to reach spreadable consistency.

Step 8: Frost and Serve

• Spread frosting over warm rolls.
• Serve immediately and enjoy!