Preheat oven to 350°F. Prepare 2 madeleine pans (18 cookies total) by spraying well with baking spray.
Add the flour, sifted cocoa, baking powder and salt to a mixing bowl, then whisk to combine. Set aside.
Add eggs, sugar, vanilla, and peppermint to a stand mixer fitted with the whip attachment. Turn the stand mixer on high and whip the mixture for about 8 minutes. When done, the batter should look thick, tripled in volume, and it should ribbon off the attachment.
Remove the bowl from the stand mixer, then add the dry ingredients to the bowl. Fold the dry ingredients into the batter until combined.
Delicately fold the melted butter into the batter until it is well combined, but the batter isn’t deflated. It may be easiest to do this in 2 steps: scoop some batter into the melted butter and fold together, then pour that into the rest of the batter, and fold until combined again.
Using a 3/4 oz cookie scoop, scoop the batter into the prepare madeleine pans, using the cookie scoop to lightly spread the batter into the pan. Place into the freezer for 15 minutes.
Remove the pans from the freezer and place into the oven to bake for 11-12 minutes. Remove from oven, allow the madeleines to cool in the pan for 30 minutes, then carefully pop each madeleine out and place onto a wire rack to cool.
When cooled, dip each madeleine into the melted chocolate and decorate with crushed candy canes.