Meditation timer that reports mindful minutes to the Health app?

Solution 1:

Sattva - Meditation Timer & Tracker

Sattva is the world’s first advanced meditation timer and tracker with challenges, trophies and guided meditations to inspire you to meditate everyday!

Has the features you requested:

• Apple health kit integration for mindfulness (minutes)
• Apple Watch app

Solution 2:

After many months of trying different apps, the one that best addresses what I need is Timeless. Sattva does not log meditation time when you meditate on the watch. Timeless does, though you have to open the iPhone app after meditating to get it to log the time.

I'll just editorialize a little and say that it's crazy that, in the Mindfulness section of the Health app, Apple promotes a bunch of apps that don't record mindful minutes.