Then mix it this way

1. Preheat oven to 180C. Line a slice tin with baking paper.
2. Place apples into the bowl. Speed 7 / 2 seconds. Remove and set aside.
3. Add butter, sugar and vanilla to bowl.
4. 4 minutes / 80C / Speed 2.
5. Add apples, cinnamon, self raising flour, oats and egg to bowl.
6. Reverse+Speed 4 / 5 seconds.
7. Pour batter into prepared tin.
8. Cook for 30 minutes or until cooked through.
9. Allow to cool completely before cutting.

Or cook like this

1. Preheat oven to 180C. Line a slice tin with baking paper.
2. Grate apples into a large mixing bowl.
3. Add butter, sugar and vanilla to a small saucepan. Melt over medium heat until butter has melted and sugar has mostly dissolved.
4. Add to apples along with cinnamon, self raising flour, oats and egg to bowl.
5. Mix to combine well.
6. Pour batter into prepared tin.
7. Cook for 30 minutes or until cooked through.
8. Allow to cool completely before cutting.