In D&D, there is no general rule that says only one spell can be cast on your turn. There is, however, a rule about casting a spell with a casting time of 1 bonus action. For more information on how spells work, see chapter 10, “Spellcasting,” in the “Player’s Handbook.” Cantrips are counted as a bonus action for that purpose, right?

— 🕶 Sage Of Song 🕶 (@SageOfSong) November 8, 2018

How does that interact with Quickened spell? Does it follow the same logic since you are converting a 1 action spell to a bonus action?

— Magic Goblin (@magical_goblin) November 8, 2018

If something in D&D changes the casting time of your spell to 1 bonus action, you now use the rules for spells that have a casting time of 1 bonus action. #DnD https://t.co/TE8qQqzKRq

— Jeremy Crawford (@JeremyECrawford) November 8, 2018