Big Magic or No Magic

You have have half the Spell Slots (rounded up so you can still get level 9 spells), but any upcastable spell you cast by expending a spell slot has the effects of the next level version while still being treated as the level of spell you cast it as. (ex. A level 14 evoker wizard casts fireball at level 5, the fireball does the damage of a level 6 fireball, but takes a level 5 spell slot and is still overchannelable.)