Eternalize

By 14th level, you've learned how to emulate the deep-seated enchantments that suffuse ancient magical sites, if only to a limited degree. When you cast a spell, you can extend its casting time into a meticulous 8-hour ritual. If you do, the spell lasts until dispelled rather than for its usual duration, and it no longer requires concentration. The spell ends as normal if an effect would cause it to do so, such as if you make an attack during the Invisibility spell. Wizards that wish to end the effect typically do so by casting Dispel Magic on themselves.

The spell you perform the ritual on must be of 5th level or lower, and it must have a duration of 1 minute or longer. It must have you and only you as its initial target, although spells that grant you an ability that targets others (such as Vampiric Touch) can be chosen.

As an additional cost to performing the ritual, the combined level of spell slots you can recover whenever you use your Arcane Recovery feature is reduced by an amount equal to the level of the chosen spell. Reduce it by an additional level if the spell usually requires concentration. You can't perform the ritual if it would bring the level total below 0. When the spell ends, it no longer counts against the total.