Hi! This is Laurie from RecipeTips.com. One of the problems with making homemade muffins that call for fresh berries is that the berries always sink to the bottom of your muffins. To prevent this from happening, do not mix the berries into the muffin batter. Fill the muffin cups with the batter alone; then simply take your berries and press them into the batter of the muffins. You want to cover the berry with as much batter as you can. And, they will sink while they are baking, but they will not go clear to the bottom. You can do this with either blueberries or raspberries. After they are baked, the blueberries will be in the center of the muffins. For more information on baking, visit RecipeTips.com.