Preheat the oven to 375°.
To make the cookies, cream together the butter and sugars with a stand mixer.
Scrape the sides and add in the eggs, and vanilla extract. Mix until combined.
Add the flour and baking powder to the mixer and mix until the cookie dough comes together.
Scoop and roll the cookies- use a generous 1/3 cup of dough for each cookie. Roll the cookies into a ball and then flatten the ball into a circle that is about 1/2 inch thick and arrange on a cookie sheet. Repeat with the remaining dough.
Place 6 cookies on each tray.Using either a skewer or the back of a thin wooden spoon, press the waffle pattern into the cookie. Create 4 grooves vertical and then 4 grooves horizontal.
Bake at 375° for 12-15 minutes or until the cookies have spread slightly and the centers of the cookies puff up and no longer look wet and glossy.
Once you pull the cookies out of the oven, make the buttercream by creaming the butter until smooth. Add 1 cup of powdered sugar at a time, mixing until incorporated before adding more.
Add in your vanilla and then just a splash of milk as needed to help bring the powdered sugar together with the butter. You want to keep this as thick as possible.
Once all of the powdered sugar has been added, use a small cookie scoop to scoop a dollop of buttercream onto your still warm cookie.
Drizzle with maple syrup and eat warm with a fork.