Arcane Teachings

You touch one willing creature, casting a spell that you know (known as the taught spell) as you do so. The taught spell must be of a level equal to or lower than the level at which this spell was cast.  You perform the somatic and verbal components for the taught spell, and supply the material components (if any), but the taught spell does not take effect. Ignore the casting time and range of the taught spell.

At any time before this spell ends, the affected creature can cast the taught spell at its lowest level, using your spell attack bonus and spell save DC. They perform somatic and verbal components, but do not need to supply material components. This time, the casting time and range do apply, and the spell does take effect. It is as if they had cast the taught spell. This spell then ends.

At Higher Levels. When you cast this spell at higher spell slot levels, you can make the taught spell of a higher level. So conceivably, you could teach everyone in town to cast wish! But I imagine your DM would resist you teaching commoners disintegrate.