The core part of the phrase is
und zwar
which is preceded by some statement, and followed by a specification of this statement:
Unser Hund läuft davon, und zwar immer wieder.
Our dog runs away, and frequently at that.
Note that zwar can be used in another way (without the und):
Das Auto ist zwar schön, aber dennoch viel zu teuer.
Admittedly, the car is beautiful, but too expensive nonetheless.
Das ist zwar unhöflich, doch oftmals notwendig.
Even though it's impolite, it's often necesary.
The first example grants some positive attribute, but rejects the whole.
The second acknowledges some negative attribute, but accepts the whole.