Berries, especially fresh blueberries, sink quickly to the bottom of muffins. If you are using fresh berries, add to the batter in muffin cups to keep them evenly spaced and from sinking. Berries that are dehydrated or frozen won't sink as easily, so that's why we use them in our muffins often. You can see in our pictures we made two sets - we used some with dehydrated berries and some with fresh berries. Save a couple of berries to add to the tops of muffins once in the pan.