Preheat oven to 350º F. Line 8-inch baking pan with parchment paper or spray with nonstick spray.
Mix melted butter with brown sugar and granulated sugar until well combined and smooth. Add in egg and vanilla and mix until very well incorporated.
Add the flour, baking powder, cinnamon and salt and mix until just barely combined. Fold in cinnamon chips.
Pour batter into prepared baking pan. Bake for about 25 minutes, or until a toothpick comes out clean.
Let the bars cool completely before cutting into them.
When ready to serve, combine powdered sugar, cinnamon, and milk until the right consistency to drizzle. The amount of milk may vary. Drizzle glaze over bars. Serve.