Preheat the oven to 375ºF. In a large bowl, cream with an electric mixer the butter and sugar until it begins to stick to the bottom and sides of the bowl. Add the egg and mix well.
Over the butter/sugar mixture, sift the flour, baking powder, and salt. Bring it all together with your hands without actually working the dough. Gentle loving mixing motion - don't squeeze and don't manhandle.