Preheat oven to 325°F (163°C). Grease and flour a 10-inch bundt pan or tube pan.
Mix dry ingredients: In a medium bowl, whisk together flour, baking powder, and salt. Set aside.
Cream butter and sugar: In a large bowl, beat softened butter and granulated sugar until light and fluffy (about 3-4 minutes).
Add eggs and vanilla: Beat in eggs one at a time, ensuring each is well incorporated. Then add vanilla extract.
Alternate adding dry ingredients and milk: Add the flour mixture in three parts, alternating with the milk (start and end with flour). Mix until just combined; don’t overmix.
Prepare cinnamon swirl: In a small bowl, combine brown sugar, cinnamon, and melted butter.
Layer the cake and cinnamon swirl: Pour about half of the cake batter into the prepared pan. Spoon half of the cinnamon swirl mixture on top and gently swirl it using a knife or skewer. Pour remaining batter over, then add the remaining cinnamon swirl mixture and swirl again.
Bake for 65-75 minutes or until a toothpick inserted in the center comes out clean.
Cool: Let the cake cool in the pan for about 15 minutes before turning it out onto a wire rack to cool completely.
Make the glaze (optional): Whisk powdered sugar, milk, vanilla, and honey until smooth. Drizzle over cooled cake.
