Simbul's Synostodweomer

D&D 2024 spell: Simbul's Synostodweomer. Source: Forgotten Realms: Heroes of Faerûn. level 7, school Transmutation, casting time 1 action, range Touch, durat...

You imbue one creature you touch with magical healing energy for the duration. Whenever the target casts a spell using a spell slot, the target can immediately roll a number of unexpended Hit Point Dice equal to the spell slot's level and regain Hit Points equal to the roll's total plus your spellcasting ability modifier; those dice are then expended.

Source: Forgotten Realms: Heroes of Faerûn, p. 145 - Licenses and attribution