Mantra of Recall

Acquisition
Signet of Capture:
 * Prophecies
 * Facet of Chaos (The Dragon's Lair)
 * Featherclaw (Snake Dance)
 * Eye of the North
 * Facet of Illusions (Magus Stones during the quest The Cipher of Lyssa)

Energy gain
This presumes Mantra of Recall is cast as often as possible (activation + recharge time) before any activation/recharge time modifiers in conjunction with ending prematurely.

Related articles

 * Gain/Lose energy skills quick reference