A California-based startup called Savor has figured out a unique way to make a butter alternative that doesn’t involve livestock, plants, or even displacing land. Their butter is produced from synthetic fat made using carbon dioxide and hydrogen, and the best part is —- it tastes just like regular butter.
Most of the CO2 savings comes from not raising cows, you’re correct that the carbon capture in the butter wouldn’t matter that much due to digestion, but it is likely not all the carbon will be released as CO2 again.