Step 1

Preheat the oven to 160 degrees celsius (fan forced).

Step 2

Take a large mixing bowl and weigh your dry ingredients (flour, sugar and custard powder) into the bowl. In a medium bowl, add your melted butter, eggs and sour cream. Use a hand mixer to combine the wet ingredients. Pour the wet ingredients into the dry ingredients and use the mixer to combine thoroughly. Set aside.

Step 3

Grab the bowl you used for the wet ingredients and add the grated apples and cinnamon and stir to combine. Add the apple mix to the large bowl and mix again to combine.

Step 4

Grease a deep 20cm x 30cm baking tin and line with baking paper.

Step 5

Add all of the crumble ingredients to a small food processor and pulse until you have chunky breadcrumbs. You can do this by hand if you like, by rubbing the butter into the dry ingredients.

Step 6

Spread the cake mixture across the baking tray and then sprinkle the crumble topping evenly over the batter. Pop in the oven for 50 mins. It will probably take an hour but oven times vary so it’s best to check. Check with a skewer and ensure there is no wet mixture on the skewer. When it’s cooked, you should see small crumbs on the skewer.

Step 7

Serve with cream, ice cream or custard.