Replenish Spell (3.5e Feat)
From D&D Wiki
Replenish Spell [Divine]
Exchanges uses of the Turn/Rebuke Undead ability for extra spells.
Prerequisite: Divine Caster level 3, Wisdom 13, Charisma 13
Benefit: You can use one use of the Turn/Rebuke Undead ability to restore a number of spell levels equal to ¼ × (your cleric level + 1) (rounded down to a multiple of ½). These must be used immediately on empty spell slots or they are lost. The spells restored are the ones that were originally prepared in the replenished slot (even if the slot was used to spontaneously cast a cure spell); if a spell was never prepared in the slot, it can't be replenished. If you use two uses of Turn/Rebuke Undead then you get twice the amount of restored spell levels, with three uses you get three times the amount of spell levels, ect.