Preheat oven to 400°.
Combine first 4 ingredients, stirring until dry ingredients are moistened and mixture holds together; set aside.
Lightly spoon self-rising flour into dry measuring cups; level with a knife. Combine 2 cups flour and next 4 ingredients in a large bowl; make a well in center of mixture. Combine pumpkin and next 3 ingredients; stir with a whisk. Add to flour mixture, stirring just until moist.
Spoon batter evenly into 16 muffin cups coated with cooking spray. Sprinkle evenly with oat mixture.
Bake at 400° for 22 to 25 minutes or until golden. Cool muffins in pan on a wire rack 5 minutes; remove from pans, and place on wire rack. Serve warm.