Bake oats in a 15- x 10-inch jelly-roll pan at 400° for 6 minutes or until lightly browned. Cool.
Combine oats and next 5 ingredients.
Cut butter into oats mixture with a pastry blender or fork until crumbly. Stir together 2/3 cup buttermilk and egg. Add to flour mixture, stirring just until dry ingredients are moistened and dough forms.
Turn dough out onto a jelly-roll pan coated with cooking spray. Shape dough into a 7 1/2-inch circle.
Combine 3 Tbsp. sugar and 1/2 tsp. cinnamon. Brush dough with 1 1/2 Tbsp. buttermilk. Sprinkle with sugar mixture and pecans.
Bake at 400° for 15 minutes or until a wooden pick inserted in center comes out clean. Cut into 8 wedges; serve immediately.