Preheat oven to 350 degrees. Grease an 8-inch square-baking pan. Combine flour, brown sugar, baking powder, and salt in a medium bowl. Add milk, shortening, egg, and vanilla; stir just until combined. Fold in cherries and pour into greased pan. Bake 25 to 30 minutes or until center springs back when lightly pressed. Cool 15 minutes. Cut into 6 rectangles and serve warm from pan with warm milk to pour over it, if desired.