  Nonlinear parabolic equations are frequently encountered in applications and
efficient approximating techniques for their solution are of great importance.
In order to provide an effective scheme for the temporal approximation of such
equations, we present a sum splitting scheme that comes with a straight forward
parallelization strategy. The convergence analysis is carried out in a
variational framework that allows for a general setting and, in particular,
nontrivial temporal coefficients. The aim of this work is to illustrate the
significant advantages of a variational framework for operator splittings and
use this to extend semigroup based theory for this type of scheme.
