Sorcerer/20th

Supreme Sorcery

At 20th level, your magical powers break what other mages would see as impossible barriers. After you cast a spell of 10-points, 11-points, or 12-points, you can cast one more spell of that slot without incurring the normal limitation of Epic Spells. Once you do this one time with any spell, you must finish a long rest before you can do so again.

You also have advantage on all Intelligence (Arcana) checks from now on.