½ cup all-purpose flour
2 tablespoon brown sugar
2 tablespoons butter, melted
Preheat oven to 400 degrees F. In a large bowl mix together the all-purpose flour, whole wheat flour, oats, sugar, baking soda, baking powder, and salt.
Add yogurt mixture to the flour mixture, and stir just until moist.
Fold in blueberries.
To make the streusel, combine together in a small mixing bowl, ½ cup of the all- purpose flour, brown sugar, and butter.
Fill muffin pans with liners. Spoon batter into each liner until it is about 2/3 full. Sprinkle evenly with streusel. Bake at 400 degrees F for 15 minutes.
Cool in pan for 10 minutes on a wire rack. Remove muffins from pan, and serve warm or at room temperature.