Preheat oven to 200°C bake.
Peel and thinly slice apple. Place in a pot with first measure of butter, vanilla and water. Cook on medium heat for about 5 minutes, until tender.
Meanwhile, melt second measure of butter in a large bowl in the microwave. Once melted, add crumble mix and stir to combine.
Transfer apples to a baking dish, about 20x20cm. Dollop over blackberry compote and cover with crumble mixture. Bake for 20-25 minutes, until crumble is golden.
Top crumble with cream or ice cream if desired.