How does the Life Domain Blessed Healer work with a Spell like Regenerate?

Question

Life Domain gives you Blessed Healer, which gives additional 2 HP + Spell Level when you cast any healing spell, and the caster gets the benefit of the spell as well.

How does this work with the Regeneration spell?

Regenerate

… The target regains 4d8 + 15 hit points. For the duration of the spell, the target regains 1 hit point at the start of each of its turns (10 hit points each minute).

So does the following happen then?

1. Initial Casting = 4d8 + 15 + 2 + 7 (Spell Level) or 4d8 + 24

2. Benefactor then gains 1 HP on their turn (10/minute)

Does this mean every turn there is a 10 HP gain per turn (1 + 2 + 7 [spell level])

That would mean a HP gain of 100 HP/minute for an hour right, a sum total of 4d8 +24 plus an additional 600 HP for the hour the spell lasts.

Or the effect only add the HP bonus on the initial casting and nothing happens during the spell duration.

Answer 1

The Life Cleric has 2 separate features which you've conflated here. The first one is Disciple of Life.

Whenever you use a spell of 1st level or higher to restore hit points to a creature, the creature regains additional hit points equal to 2 + the spell’s level.

The second one is Blessed Healer.

When you cast a spell of 1st level or higher that restores hit points to a creature other than you, you regain hit points equal to 2 + the spell’s level.

Blessed Healer is simple. You get healed when you cast a spell. So Regenerate will heal you for 9 hp, but only when you cast it.

Disciple of Life is a bit less clear. It is triggered "when you use a spell to restore hit points to a creature". There are 2 interpretations of this:

1. The first is that using the spell is the same thing as casting it, and therefore only the initial 4d8 + 15 gets the +9 hp from Disciple of Life.
2. The second is that you're using the spell to restore hit points every time it restores hit points. In that case, the target would indeed gain 10 hp every turn for the duration.

Unfortunately, there is basically nothing in the rules to help decide which interpretation is correct. "Using" a spell is not common terminology - almost everything in the rules talks about casting a spell, not using it.

However, a similar question was answered in the official Sage Advice Compendium.

If I’m a cleric/druid with the Disciple of Life feature, does the goodberry spell benefit from the feature? Yes. The Disciple of Life feature would make each berry restore 4 hit points, instead of 1, assuming you cast goodberry with a 1st-level spell slot.

If Disciple of Life works every time someone eats a goodberry, it should certainly work every time someone is healed by Regenerate. So yes, Regenerate cast by a Life Cleric will heal 10 hp every turn.

Answer 2

My understanding would be Disciple of Life would trigger when someone is healed from the result of a spell. Thus, the Regenerate spell would heal 1+2+7(10)hp every turn because the healing is a result of the spell that was cast.

But yeah, Blessed Healer is pretty clear cut.

Answer 3

Blessed Healer (PHB p.60)

Beginning at 6th level, the healing spells you cast on others heal you as well. When you cast a spell of 1st level or higher that restores hit points to a creature other than you, you regain hit points equal to 2 + the spell’s level.

You get the benefit when you cast the spell, not at any other time. So the caster would gain 9 HPs when they cast the spell on someone else.

Answer 4

You are right in general but you are also off by a factor of 10.

Normally Regenerate heals for 10hp per minute for an hour, and that's 600hp (10hp*60minutes) now it is healing for 100hp per minute or 6,000hp per hour.