Preheat oven to 350°.
Lightly spoon flour into dry measuring cups, and level with a knife. Combine flour, sugar, and salt in a large bowl; stir well with a whisk. Cut in butter with a pastry blender or 2 knives until mixture resembles coarse meal. Remove 1/3 cup flour mixture; place in a small bowl. Stir in pine nuts and cinnamon; set aside.
Combine the remaining flour mixture, sour cream, and the next 6 ingredients (sour cream through egg) in a large bowl. Beat with a mixer at medium speed until well blended. Pour the batter into a 9-inch round cake pan coated with cooking spray. Arrange the pear slices evenly over the batter. Sprinkle with pine nut mixture. Bake at 350° for 45 minutes or until a wooden pick inserted in center comes out clean; cool completely on a wire rack.