My (GF) "Gramps" made it when I was little. He used plenty of butter and fresh lemons. That is all I remember
( When cooling in a jar it was a pale yellow. It was rich, tangy but not overly sweet.
Anyone heard or knows the recipe of Lemon Butter?
My daughter is lying about me and editing me out of her life.

for your response and your time. This morning I checked out the recipe from the link you posted. Unfortunately, my Gramps used 1lb or (500g) of butter and several lemons. 

