Preheat the oven to 180℃ (160℃ fan)/350°F/gas mark 4. Grease and line a rectangular baking tin about 23 x 27cm( 9 x 11 in).
Beat 250g butter and 250g sugar together until light and fluffy. Add 4 eggs, one at a time beating well after each addition.
Beat in 1 tablespoon cinnamon, then add 500g diced apple and mix well.
Gently fold in 300g flour until well combined. Spoon into the prepared tin and spread level. Sprinkle 2 tablespoons of demerara sugar if using
Bake in the centre of the oven for 45 minutes, until risen and golden. The cake will spring back when gently pressed in the centre with your finger.
Allow to cool in the tin. Transfer to a board and cut into squares to serve.
Video
Notes
Storein an airtight container in a cool place for up to 1 week.FreezeThe cake freezes well for up to 3 months.Nutrition information is approximate and is meant as a guideline only. (It does not include the optional demerara sugar.)