Preheat your oven to 350°F (175°C).
Grease and flour a bundt pan.
In a large bowl, mix flour, sugar, baking powder, and salt.
In another bowl, whisk together milk, melted butter, eggs, and vanilla.
Combine the wet and dry ingredients until just mixed.
In a small bowl, combine brown sugar and cinnamon.
Pour half of the batter into the bundt pan.
Sprinkle the cinnamon-sugar mixture over the batter.
Add the remaining batter on top and swirl gently.
Bake for 40-45 minutes or until a toothpick comes out clean.
Allow to cool for 10 minutes before inverting onto a plate.
Mix powdered sugar and milk for glaze, then drizzle over the cooled cake.