Cream 1/2 cup butter and granulated sugar. Mix in eggs and vanilla; beat well. Stir in flour, baking soda, baking powder, and salt alternately with sour cream. Fold in apple and pear. Spread batter in pan.
Mix remaining ingredients and sprinkle evenly over batter.
Bake at 350 degrees until wooden pick comes out clean, 45-55 minutes.