Consume Flame

You touch an open fire and extinguish it, absorbing its power. You gain temporary hit points based on the size and power of the fire. Touching a source of fire as part of this spell doesn't harm you. If the consumed fire is nonmagical and the size of a Medium creature or smaller, you gain 5 temporary hit points. The number of hit points increases by 5 for each size category above Medium.

If the consumed fire is an ongoing spell effect, the spell ends and you gain a number of temporary hit points equal to 10 +5 per spell level.

You can also consume the heat from lava, cooling and hardening it in the process. You gain temporary hit points equal to the radius (in feet) of the area of lava cooled, to a max radius of 30ft.