First mix the flaxseed with the water to make your flax egg (if using an alternative prepare as directed to make 2 eggs - or beat 2 eggs). Set aside.

Cream the butter and the sugar in a large bowl.

Add the flour, baking powder and salt and start to combine. Leave roughly mixed.

Pour in your egg, add the vanilla and gently mix. Add the milk as required to make a firm but creamy batter.

Peel, core and dice the apples. Sprinkle the cinnamon and flour over, then scoop up the apples with your fingertips and drop back down to ensure they are all dusted with both. Add the apples to the cake batter and fold through.

Spoon the batter into a prepared tin (I used a round glass dish) and level out.

Put the flour in a small dish and rub the butter in using your fingertips, add the sugar and mix until you have a mixture resembling breadcrumbs.

Sprinkle the crumble topping evenly over your cake and bake at Gas Mark 4 (350f / 180c) for 50-60 minutes. The cake is ready when a skewer inserted into the centre comes out clean and the top is golden brown.

Remove from the oven and allow to cool in the tin for 20 minutes. Run a knife around the outside of the cake to loosen then tip out and finish cooling (the right way up) on a wire rack. Slice and serve!

Enjoy!