Preheat oven to 350F.
Sift together all dry ingredients.
Slowly add all remaining ingredients except for mixed berries, being careful to not over-mix. Gently fold in mixed berries. (If you are using nuts or whole oats for texture, you can add these in with the berries as well).
Divide batter evenly in a lightly greased muffin pan.
Bake for 18-22 minutes or until golden brown and toothpick inserted comes out clean.