My 11 month old has recently become a very fussy eater so I will be moving him from steamed to sautéed vegetables. Is it better to cool with butter or olive oil?

Just to add on that you should use unsalted butter since your baby is below 1 year of age. As for me I think I would alternate my uses. So sometimes butter and sometimes olive oil. Don't have to be too strict about one. You could also consider using extra virgin coconut oil. Coconut oil is rich in lauric acid which boosts baby’s immune system and helps in digestion. You can also use it for many other uses as well! http://sg.theasianparent.com/virgin-coconut-oil-benefits-for-babies/