Sift together flour, baking powder and 1/2 tsp salt. Cream together butter, 1/2 cup sugar and 1/2 tsp salt. Blend 2/3 dry ingredients into creamed mixture a little at a time. Add remaining dry ingredients. Work mixture together with fingers to form a crumble. Set aside 1 cup of crumble. Pat remaining crumble over sides and bottom of greased 8-inch glass or deep dish style pie plate. In a bowl, stir 2 tbsp. sugar and the cinnamon into sour cream, then add well-beaten egg. Drain pear slices, arrange over the crumb mixture in pie plate. Spread sour cream mixture over the pears and sprinkle with reserved 1 cup of crumble. Bake in preheated 350 degree oven for 45 minutes.