In large bowl, cream butter and sugar until light and fluffy. Combine the eggs and milk. Combine the flour, cornmeal, baking powder and salt, add to creamed mixture alternately with egg mixture. Pour into a greased 13 X 9 inch baking pan. Bake at 400 degrees for 22-27 minutes or until a toothpick inserted near the centre comes out clean. Cut into squares and serve warm.