"Once you think about it, his potions taste like lemonade."
The Health Potions are 1-cost spells that restores health to any target equal to the damage the Lifesteal cards has dealt. This means that if you had a Chillblade Champion, you would get a 1-cost spells that restore 3 Health. If the Chillblade Champion had 5 attack, you would get a 1-cost spell that restored 5 Health etc.
Note that this works also for spells like Spirit Lash, but it will instead give one potion for all damage dealt instead of filling up your hand. This will have synergy with Hallazeal the Ascended, since it technically gives damaging spells Lifesteal.
Example of Health Potion:
Created by Chillblade Champion