  The stability of periodically placed slabs occurring in neutron stars
(lasagna phase) is examined by exact geometrical methods for the first time. It
appears that the slabs are stable against any shape perturbation modes for the
whole range of volume fraction occupied by the slab. The calculations are done
in the framework of the liquid drop model and obtained results are universal -
they do not depend on model parameters like surface tension or charge density.
The results shows that the transition to other pasta shapes requires crossing
the finite energy barrier
