Cinnamon Roll Cake

For the cinnamon swirl:
– 1/2 cup unsalted butter, softened
– 1 cup brown sugar
– 2 tablespoons all-purpose flour
– 2 teaspoons ground cinnamon

For the glaze:
– 1 cup powdered sugar
– 2 tablespoons milk
– 1/2 teaspoon vanilla extract