Place the apple pieces in a saucepan with a little water and the caster sugar. Cook until the apples are tender.
Place the apples and their juices in a lightly greased oven proof dish.
Mix the batter ingredients with a spoon until batter is smooth. Drop batter on top of the aplpe mix with a spoon (DO NOT STIR), as evenly as possible. (The batter will spread over the top while being cooked.)
Cook in a preheated 180C oven for 35 – 40 minutes, or until apples are tender and the crust is golden brown.
Notes & Tips
Optional: you can add a cinnamon quill and some lemon zest to the apples when cooking initially to add some more flavour to the crumble.