Peel and core the apples. Chop them into fairly large pieces and place into the bowl of the Redmond multicooker along with the sultanas.
Combine the soft brown sugar, cornflour, cinnamon and nutmeg together in a small bowl and stir into the apple and sultanas until the apples are coated completely. Most of the sultanas will sink to the bottom.
To prepare the topping, mix the porridge oats, wholewheat flour, sugars, spices and salt together in a large bowl.
Rub the butter in with your fingertips until it resembles coarse breadcrumbs.
Stir in the finely chopped hazelnuts and sprinkle over the top of the apple mixture.
Select the Cake setting on the Redmond Multicooker and select a 30 minute time. Press Start.
The apple and hazelnut crumble will be ready to serve at the end of the 30 minutes cooking time, but the apples will still have some texture (the way I like it). If you leave it to keep warm for a further 10-15 minutes the apples will soften some more.
I use a mixture of apples in my crumbles but I prefer the Bramley apple variety. Feel free to replace the hazelnuts with walnuts or almonds.