Activate the Yeast: Mix warm milk, sugar, and yeast in a bowl. Let sit 5–10 minutes until foamy.
Prepare the Dough: Add melted butter, egg, and salt. Gradually mix in flour and knead until smooth. Cover and let rise 1 hour or until doubled.
Make the Filling: Combine softened butter, brown sugar, cinnamon, and vanilla.
Shape the Rolls: Roll dough into a rectangle, spread filling, roll tightly, and slice into equal pieces.
Second Rise: Place rolls in a baking dish, cover, and let rise 30–40 minutes.
Bake: Bake at 180°C / 350°F for 20–25 minutes until lightly golden.
Make the Glaze: Whisk powdered sugar, butter, milk, and vanilla until smooth.
Serve: Drizzle warm rolls generously with glaze. Enjoy!