D&D 5E how to handle action surge and quicken spell

[DaveDash]

RAW allows for using action surge to cast a 2nd spell. Action surge explicitly allows it and no other rule forbids it. Not sure where you are getting that RAW doesn't allow it?

Indeed. And Jeremy Crawford on Sage Advice clarified you can do it.

Considering you need two levels of fighter which put you two levels behind a pure caster - it's not that strong.

 

[guachi]

He's talking about using a Bonus Action to cast a spell. That interferes with the spells allowable for your action, whether it's your regular action or an action granted by Action Surge.

 

[rczarnec]

He's talking about using a Bonus Action to cast a spell. That interferes with the spells allowable for your action, whether it's your regular action or an action granted by Action Surge.

Exactly. If a character casts a bonus action spell, then the only other spells that can be cast on that turn are cantrips with a casting time of 1 action. So if you cast a bonus action spell (or quicken one into a bonus action), the character is limited to cantrips for any other spells that turn.