I think we should start with the Cathedral of the Nativity of the Theotokos in Ufa. Like many other post-Soviet cathedrals, it was originally just a parish church - even closed under the Communists.
In Ufa, however, instead of restoring the old cathedral, this small church, which was "temporarily fulfilling" its duties, was decided to be transformed - given the features of noble classicism and rebuilt to make it worthy of hosting a cathedra.