Activate the yeast: In a stand mixer bowl, combine warm milk, yeast, and 1 tsp sugar. Let sit for 5-10 minutes until foamy.
Mix wet ingredients: Add remaining sugar, eggs, melted butter, and salt. Mix on low speed.
Add flour: Gradually add flour until a soft dough forms. Knead for 5-7 minutes until smooth.
First rise: Place dough in a greased bowl, cover, and let rise for 1 hour or until doubled.
Mix brown sugar and cinnamon in a small bowl. Set aside.
Roll out dough: On a floured surface, roll dough into a 16x12-inch rectangle.
Add filling: Spread softened butter over dough, then sprinkle cinnamon sugar evenly.
Roll & cut: Roll tightly into a log. Cut into 8-10 slices.
Arrange in pan: Place slices in a parchment-lined loaf pan. Cover and let rise 30 minutes.
Preheat oven to 350°F (175°C).
Bake for 25-30 minutes until golden brown. Cover with foil if browning too quickly.
Whisk powdered sugar, milk, and vanilla. Drizzle over warm bread.
