1. Preheat oven to 400°.
2. To prepare muffins, weigh or lightly spoon flours into dry measuring cups; level with a knife. Combine flours, oats, and next 4 ingredients in a large bowl, stirring with a whisk. Make a well in center of mixture. Combine yogurt and next 4 ingredients, stirring with a whisk. Add yogurt mixture to flour mixture, stirring just until moist. Fold in blueberries. Spoon batter into 24 muffin cups coated with cooking spray, filling two-thirds full.
3. To prepare streusel, weigh or lightly spoon flour into a dry measuring cup; level with a knife. Combine flour and next 3 ingredients, stirring until crumbly. Sprinkle streusel evenly over batter.
4. Bake at 400° for 15 minutes or until muffins spring back when touched lightly in center. Cool in pans 10 minutes on a wire rack; remove from pans. Serve warm or at room temperature.
Young Chefs can:
Measure blueberries and add to batter
Sprinkle streusel over batter
Older Chefs can:
Combine dry ingredients
Help spoon batter into muffin cups