It is an invention of Ryan Brigg, whose determination to improve mole rat meat led him to hole up with raiders in the Jury St. tunnels. The player character can interact with the equipment to prepare mole rat wonder meat, from one regular mole rat meat and a bottle of wonderglue.
It is located in a small room in the northeast of the Jury St. tunnels. To find it enter via Jury Street Metro station, head south down the escalator, through the left tunnel, until one finds a door on the left side of the tunnel. Go through the door and head down. It can be seen opposite the door.
The wonder meat maker appears only in Fallout 3.