Step 1: In a bowl, combine warm milk, yeast, and 1 tbsp sugar. Let sit for 5 minutes until foamy.
Step 2: Add melted butter, eggs, remaining sugar, flour, and salt. Mix until a soft dough forms.
Step 3: Knead dough on floured surface for 5 minutes until smooth. Place in greased bowl, cover, and let rise for 1 hour.
Step 4: Roll dough into a 16×21 inch rectangle. Spread softened butter evenly over dough.
Step 5: Mix brown sugar and cinnamon, then sprinkle evenly over buttered dough.
Step 6: Roll dough tightly from long edge and cut into 12 equal slices.
Step 7: Place rolls in greased 9×13 inch baking pan. Cover and let rise for 30 minutes.
Step 8: Preheat oven to 350°F. Bake rolls for 25-30 minutes until golden brown.
Step 9: Whisk powdered sugar, milk, and vanilla to make glaze. Drizzle over warm rolls before serving.