In a large pan, boil water and sugar until sugar is dissolved. Add butter, stir to dissolve and cool. Add mint extract and flour mixed with baking powder. Stir well and let stand for 20 minutes.
Roll out on a floured board to finger thickness. Cut in 1-inch circles and bake on a greased and floured cookie sheet in a preheated 350-degree oven for about 10 minutes. Cookies will still be white on top, slightly brown on bottom.