With an electric mixer, cream butter and sugar. Add eggs and mix. Add flour, baking powder, and salt. Mix well, until creamed. Spread a liberal amount of the dough into a greased 15X11-inch pan. Cover with cherry pie filling. Scatter remaining dough by teasponful over filling.
FOR STREUSEL TOPPING: In small bowl, mix sugar and flour. Cut in butter with a pastry blender until crumbly. Stir in nuts. Sprinkle streusel topping over cake and bake at 180ºC or one hour.