1. Prepare the Crust:

1. Preheat oven to 375°F (190°C). Line baking sheets with parchment paper.
2. In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the egg and vanilla extract. In a separate bowl, whisk together the flour, baking powder, and salt. Gradually add the dry ingredients to the wet ingredients, mixing until a soft dough forms.
3. Roll dough into 1-inch balls. On the prepared baking sheet, shape each ball into a ring, pressing your thumb through the center to create a wreath shape. Bake for 7-9 minutes, or until the edges are just beginning to turn golden. Let cool completely on a wire rack.
4. For the glaze, whisk together powdered sugar, milk, and peppermint extract until smooth. Divide the glaze in half. Color one half with a few drops of red food coloring. Drizzle the white and red glazes over the cooled cookies and immediately sprinkle with crushed candy canes.