Spellcasting feature from the Cleric, Druid, or Wizard class
Instead of preparing spells normally, you fix each spell slot precisely in your mind, in the manner of wizards long past. When you would prepare spells when you finish a long rest, you record which spell you will use with each of your spell slots, picking from among the spells you could cast using it.
These spell slots can’t be expended for any purpose other than casting their assigned spells, but can be recovered and used to cast any spell. Additionally, you gain a bonus spell slot of each level for which you have spell slots, to which you do not assign a particular spell and can cast normally.
For example, a 3rd-level wizard has four 1st-level spell slots and two 2nd-level spell slots. Using
this feat, the wizard must assign each spell slot to a spell; for example, three 1st-level magic missiles, one 1st-level sleep, one 2nd-level scorching ray, and one 2nd-level mirror image. The wizard also has one bonus 1st-level spell slot and one bonus 2nd-level spell slot, through which they can cast any spell they have recorded in their spellbook.