Roughly chop apples into chunks.
Add chopped apples, sugar if using, vanilla, cinnamon and water to pan and cook until tender.
While the apple mix is cooling, heat oven to 170 °C.
Butter the pan edges and line the base with baking paper (this makes it easier to remove from pan).
Gently press pastry into pan.
Spoon apple filling into pastry lined pan and spread around to an even height.
For the pastry top, use left over pastry and cut into thin strips. Decorate the top with pastry strips into a criss cross pattern.
Trim edges of pastry off with a sharp knife.
Bake for 30-40 minutes until golden brown.
Once cool, dust with icing sugar and serve with whipped cream or ice cream.