PREHEAT oven to 350ºF. Beat butter with electric mixer on medium speed until creamy. Add flour and sugar; beat on low speed until crumbly. Remove 1/3 cup of the butter mixture; set aside. Add baking powder, baking soda, chocolate, egg and milk to remaining butter mixture in bowl. Stir just until dry ingredients are moistened.
SPREAD one-third of the batter into greased 9-inch springform pan. Place pear halves, cut sides down, in a circular pattern over batter. Drop spoonfuls of remaining batter over pears; spread to evenly cover pears. Sprinkle with the reserved crumb mixture and pecans.
BAKE 1 hour 10 minutes or until toothpick inserted in centre comes out clean. Cool.