Recipes for baked goods often call for the cold ingredients to come to room temperature before mixing. This is especially helpful when using melted butter, coconut oil, or honey which tend to re-harden upon contact with cold ingredients. If this happens, I very gently and slowly heat the batter in the microwave until I can incorporate the ingredients fully–but not cook them.
Combine flours, oats, sugar, baking powder, baking soda and salt in a large bowl. Make a well in center of the mixture and set aside.
Combine the yogurt, milk, oil, vanilla, egg, and banana in another large bowl.
Gently fold in the berries, stirring just enough to incorporate.
Add the yogurt and fruit mixture to the flour mixture and stir just until moistened.
Using a large ice cream scoop, fill about 20 greased muffin cups.
Sprinkle with one of the desired toppings if you wish, and then bake for 15-17 minutes or until the muffins pass the toothpick test. Be careful not to over-bake.
Cool in pans for 10 minutes, and then remove to a wire rack.