Stir together flour and brown sugar in a large bowl. Cut 3/4 cup butter into flour mixture with a pastry blender or 2 forks until crumbly. Press 2 3/4 cups crumb mixture evenly on the bottom of a lightly greased 13- x 9-inch pan.

Stir together sour cream, egg, and baking soda; add to remaining crumb mixture, stirring just until dry ingredients are moistened. Stir together granulated sugar and cinnamon. Pour sour cream mixture over crumb crust in pan; sprinkle evenly with cinnamon mixture and pecans.

Bake at 350° for 25 to 30 minutes or until a wooden pick inserted into center comes out clean.

Drizzle with powdered sugar glaze if desired.