Will of fire

Use your will to cover your hand in fire and dash forward to hit your target

Before hitting a target cast Will of fire to dash an extra 10 feet to punch the target doing Unarmed strike + 6D6 of fire damage, knocking them back 10 feet and knocking them prone, the creature gets a Dex save to move out of the way and an opportunity attack on the caster.  

Add an extra 2D6 if spell is casted at a higher level