Preheat oven to 350 degrees.
In a mixing bowl, beat the butter and sugar.
Add in the egg and vanilla and beat well.
In a small bowl, combine the flour, cocoa powder, salt, and baking powder. Add it into the sugar mixture and mix until combined well.
Use a cookie scoop to drop cookie dough onto cookie sheets and bake for about 8-10 minutes.
Cool the cookies completely.
Melt the white chocolate per package directions and dip each cookie into the chocolate until coated halfway.
Put 2 candy cane sprinkles on the white chocolate and sprinkle crushed candy canes around on the chocolate. Let harden.