So, I made it, and all seemed well, until I took the lid off the blender, and caught a whiff. It smelled slightly flowery.
I do not recall my aunt's ever smelling flowery.
In hindsight, I probably should have washed the blender first, it had been in storage for over a year and came from a neighbour before that, so who knows what has been in it, although the lid was on, and it wasn't dusty inside.
Also, I used olive oil, and I think my aunt just uses a vegetable oil, so that could account for the yellower colour as well as the flowery smell. I am really hoping that is it.
I haven't tried it yet, I am a little afraid to. I only made 1/2 cup of butter worth in any case, so it is not too much of a tragedy if it is inedible.
Hopefully someone will let you know if I die of suspiciously flowery Better Butter. Maybe they will put that in my tombstone.
*Better Butter recipe: equal parts softened butter (eg, 1lb of butter =2 cups) and some kind of vegetable oil (olive, canola, sunflower), blend in a blender until combined, put in a container with a lid and refrigerate.