Preheat oven to 375 degrees. Lightly oil 10 muffin cups or spray with a nonstick cooking spray. Place oats in a blender container and blend until it has the consistency of flour. Place in a large bowl and add baking powder. Mix well. Stir in raisins. Place milk in a medium bowl. Add lemon juice and let stand 1 minute. Add remaining ingredients. Beat with a fork or wire whisk until blended. Add to dry mixture, mixing until all ingredients are moistened. Divide batter evenly into prepared muffin cups. Bake 20 minutes, until a toothpick inserted into the center of a muffin comes out clean. Remove muffins to arack to cool.