Preheat oven to 180 degrees C. Grease a 20x30cm baking dish.
In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the egg and vanilla. Combine the flour, baking powder and salt; stir into the creamed mixture. Reserve 1 1/2 cups of the dough and spread the rest into the bottom of the prepared pan. Cover this layer evenly with cherry pie filling. Drop the rest of the dough by spoonfuls on top of the cherry layer and spread to cover the best you can.
Bake for 35 to 40 minutes in the preheated oven, until top is golden. Let cool completely before cutting into bars and icing.