If you can have a half and half pizza I see no reason you can’t have a half and half cake.
A bigger cake or slice tray is preferable as it give you a little wiggle room for in tray mixing.
As seen here in below picture I made a basic butter cake then poured the batter in to a slice tray (28x18cm).
I sprinkled some chocolate chips on top, carefully with a skewer (my implement of choice when mixing like this) I pushed some chips down into batter and sort of stirred them in, more on top. Topped with shredded coconut.
The other half I had a fresh pear that I peeled cored and sliced, place on the top of the other half then sprinkled with a little mixed spice.
Baked as usual. Cooled to half way in the tray then turned onto a wire rack.
An easy way to give a little variety. Works just as well with a chocolate cake mix or other.
Apples or peaches or banana for other fruits and sultanas or mixed fruit for the other side, the choices are yours.