Cascading Buffer

When you cast this spell, reduce the damage of the triggering attack by 1 plus an amount equal to the spell slot level consumed to cast it. Additionally, you gain another Reaction until the beginning of your next turn. This reaction may only be used to cast this spell again at a spell level lower than what it was just cast at but without requiring a spell slot. 

At Higher Levels:

When you cast this spell at a level higher than one, it reduces an additional 1 damage for each level above the first.