1. Preheat oven to 350 F. Line 40 muffins tins with paper liners.
2. Combine dry ingredients in a medium bowl; mix well.
3. Add remaining ingredients, reserving 1 cup walnuts. Stir just until combined.
4. Spoon into prepared muffins tins. Sprinkle with reserved walnuts.
5. Bake for 20 to 25 minutes. Store in a tightly closed container.