Gaining

Heavy cream alternative?

You could look into canned coconut milk, it has a lot of the fat still in it. But:
- I don't know how healthy a fat it is
- I suspect part of heavy cream's near magical powers are due to its dairy nature, that it is basically meant to be perfectly digestible when we are babies so for those of us who can still consume, it is still pretty much the perfectly digestible food, in a form that our bodies make use of the most easily.
3 years