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.
We have made this a few times and it is actually excellent on the BBQ! It was too hot to preheat oven etc so once our lamb was done, I divided the batter and pears between 3x 1/2lb takeaway foil containers and we put them on our charcoal BBQ (direct heat). It only took 10 mins, they were done to perfection and now hubby is keen to get the BBQ out just so we can have "BBQ Pear Cake". It's excellent and even less effort than cooking in the oven. A gem! Doing this again tomorrow for guests.