When do you add the olive oil in the crust portion of of the recipe?

Good question. It's not really clear in the recipe or the comments. I would probably add it to the butter when cooking the potatoes for the crust, but that's just me. Hoping the author sees this and responds.

According to similar recipes, when you prepare the cast iron pan to take the potatoes (after they've been frozen and thawed)...step 4 when the butter is added (I would add both butter and olive oil).