Algae cooking oil because it's vegan and 75% lower in saturated fats than olive oil. It's virtually all oleic acid, an omega-9 that is the main component of olive oil

Olive oil has its own tasty flavors that should not be forgotten.

If you really miss butter flavor, you can add some Flavacol to your vegetable fat of choice. Its the industry secret for that yellow dust on popcorn: https://shop.gmpopcorn.com/products/color-free-flavacol-2419. Its vegan too :)