Preheat the oven to 350°F and grease a loaf pan or line it with parchment paper
In a medium bowl, whisk together the flour, cocoa powder, baking soda, baking powder, and salt, then set aside
In a large bowl, whisk together the melted butter, brown sugar, eggs, and vanilla extract until smooth and glossy
Mix in the sour cream and milk until fully combined
Gradually fold in the dry ingredients until a thick batter forms
Stir in the chocolate chips and pour the batter into the prepared loaf pan, spreading evenly
Bake for 45–55 minutes, or until a toothpick inserted into the center comes out clean
Allow the loaf to cool completely before adding the glaze
To make the glaze, whisk together powdered sugar, milk, and peppermint extract until smooth
Drizzle the glaze over the cooled loaf and finish with crushed candy canes on top
