Step 1: In a large bowl, combine warm milk, yeast, and 1 tbsp sugar. Let sit for 5 minutes until foamy.
Step 2: Add remaining sugar, melted butter, eggs, and vanilla to yeast mixture. Mix well.
Step 3: Gradually add flour and salt, mixing until a soft dough forms. Knead for 5 minutes.
Step 4: Place dough in greased bowl, cover, and let rise in warm place for 1 hour until doubled.
Step 5: Roll dough into 12×18 inch rectangle on floured surface.
Step 6: Spread softened butter evenly over dough, then sprinkle with brown sugar, cinnamon, and sprinkles.
Step 7: Tightly roll dough from long side into log. Cut into 12 equal slices.
Step 8: Place rolls in greased 9×13 inch baking pan. Cover and let rise 30 minutes.
Step 9: Preheat oven to 350°F. Bake rolls for 25-30 minutes until golden brown.
Step 10: While baking, beat cream cheese, butter, powdered sugar, and vanilla until smooth. Add milk to reach desired consistency.
Step 11: Let rolls cool 10 minutes, then spread frosting over warm rolls. Serve immediately.