Preheat the oven to 200C/gas 6. Line the sides and base of a 20 x 20cm square cake tin with parchment paper. This is key otherwise your cake will stick.

Whisk the eggs, caster sugar and vanilla extract in a large bowl until the mixture is thick, I use my stand mixer for this.

Melt the butter in a saucepan with the milk, then pour onto the eggs, whisking all the time. Sift in the flour, cinnamon and baking powder and fold carefully into the batter so that there are no lumps of flour. Pour the mixture into the prepared tin..

Arrange the apple slices over the batter and bake in the oven for ten minutes, then reduce the oven temperature to 180C/gas 4 and bake for a further 20–25 minutes or until well risen and golden brown.

Remove the cake from the oven and allow to cool in the tin.