Belial's Book of Shadows

When casting this spell, choose 3 spells you have prepared which are of the same or lower level than the spell slot used to cast this spell. Once the casting of the spell is completed, those spells become unprepared and you may instead choose to replace them each with a spell of the same or lower level than the spell slot used to cast this spell.

At Higher Levels: When you cast this spell using a spell slot of 3rd level or higher, you can choose an additional prepared spell for each slot level above 3nd.