1. Preheat your oven to 350°F and generously grease your Bundt pan.

2. Mix together the cinnamon swirl ingredients – brown sugar, ground cinnamon, and melted butter – and set it aside.

3. In a large bowl, cream the butter and sugar until light and fluffy, about 4-5 minutes using an electric mixer.

4. Add the eggs one at a time, followed by the vanilla extract.

5. In a separate bowl, whisk together the flour, baking powder, and salt.

6. Alternate adding the dry ingredients and milk to the butter mixture, starting and ending with the flour mixture.

7. Spread half of the batter into the prepared Bundt pan, then sprinkle the cinnamon swirl mixture evenly over the top.

8. Add the remaining batter, and use a knife to gently swirl through the layers.

9. Bake for 50-60 minutes, or until a toothpick inserted into the center comes out clean.

10. Allow the cake to cool in the pan for 10 minutes before inverting it onto a wire rack to cool completely.

11. Whisk together the powdered sugar, milk, and vanilla extract until smooth and pourable.

12. Drizzle the glaze over the cooled cake.