Heat the oven to 180C. Grease and line the base of a 21cm round spring form tin with baking paper.
To prepare the apples, place apples cut-side-down on a board and thinly slice, but only cut halfway through so the apples stay intact. Places in a bowl and add the lemon juice and sugar. Toss gently to combine and set aside.
To make the cake, beat the butter and sugar together until light and creamy. Add the egg yolks and beat well then add the honey and vanilla extract beating until combined.
Sift the flour, salt, baking powder and cinnamon over the butter mixture and fold in. The mixture will be quite stiff.
Beat the egg whites until soft peak forms. Fold in ⅓ of the egg white into the cake mixture to loosen, then another ⅓, then finally the remaining egg white. Place mixture in the prepared tin, smoothing the top. Arrange the apple halves, rounded-side-up over the cake mixture. Pour any lemon juice and sugar over the apples.
Place in the oven and bake for 40-50 minutes or until a skewer inserted in the centre of the cake comes out clean. Remove from the oven and leave for 10 minutes before removing from the tin to a wire cooling rack. Brush or pour over the warmed honey. The honey will be absorbed by the cake.
Cake can be stored in an airtight container for up to 3 days.