1. Preheat oven to 350°.
2. Weigh or lightly spoon flours into dry measuring cups; level with a knife. Combine flours, granulated sugar, and next 5 ingredients (through salt) in a medium bowl; stir with a whisk. Make a well in center of mixture. Combine buttermilk, melted butter, oil, and eggs; stir with a whisk. Add to flour mixture, stirring just until moist. Fold in chocolate minichips.
3. Place 15 paper muffin cup liners in muffins cups; coat liners with cooking spray. Spoon batter into prepared cups. Bake at 350° for 25 minutes or until a wooden pick inserted in center comes out clean. Cool 10 minutes in pan on a wire rack; remove from pan.