Needs more butter

One of my wife's favourite flavours is a peanut butter and toffee that I made her. The original one I made her was from HC concentrates. After she read a few forums she said that there was lots of good feedback about the Capella peanut butter.... so I got some and made a few small batches, steeped them a few days and got the thumbs up for ratio of peanut butter to toffee. Then I mixed a 30ml bottle and let it steep for 3 weeks. Her comments now are "this is excellent, but it could be little more 'buttery'".
Are there any additives that would give it a bit more butteriness? I'm thinking along the lines of the way EM adds sweetness.

 

There is a butter ingredient but it has a bad rep in the vaping community be.comse it has been linked to popcorn lung a pretty bad disease. You would have to look at alternatives like cream flavour or maybe even custard.

 

Is it this? -> Raw Ingredient Molecule Acetyl Valeryl

 

No that one is probably safe, the one that isnt is this one Diacetyl - Wikipedia, the free encyclopedia

 

Thanks for that CCC.

Does anyone have any experience with using the stuff I linked in a recipe?