Fold the flour into the cake batter one third at a time.
Times,Sunday Times
The batter may be a little looser than you'd expect from a cake batter, but don't worry.
Times, Sunday Times
Mix pecans into the remaining flour; add to cake batter; stir to blend well.
Smithsonian
I would sit on a bench as she mixed a cake batter or made a pudding.
Times, Sunday Times
Add half the apple to the cake batter and mix in.
The Sun