  The BV-Laplacian $\Delta$ in quantum field theory is singular, by
construction, but can be regularized by deforming the classical BV-action.
Taking inspiration from string theory we describe a non-local deformation of
the latter by adding stubs to the interaction vertices while keeping classical
BV-invariance manifest. This is achieved using a version of homotopy transfer
resulting in a non-polynomial action for which the quantum master equation is
now well defined and will be satisfied by adding additional vertices at loop
level. The latter can be defined with the help of standard regularization
schemes and is independent of the definition of $\Delta$. In particular, the
determination of anomalies reduces to the standard text-book calculation.
Finally, we describe how the deformed (quantum) action can be obtained as a
canonical transformation. As an example, we illustrate this procedure for
quantum electrodynamics.
