Generally speaking, you can add 1 ounce of oil to 1 pound of wax. You can weigh out the oil, or just keep it simple and add 2 tablespoons.

Becky- This place has Peanut Butter Cookie. Not the same, but maybe you can do something with it. Here is a link that might be useful: Peanut Buuter Cookie Scent

Here's what I've discovered about palm wax. Since it has a higher melting point, I had to use a larger wick to get a decent wax pool. I also experienced the lack of scent throw and ended up using about 2 oz per pound. Palm wax makes pretty candles but regular pillar (paraffin) or container (soy) wax might be easier ... especially if you're new to this.

I also have no interest in the company but many stores in the Austin (TX) area carry their candles and I can second Patricia's recommendation. I love good candles and these really do have a lot of scent and last a long time (and the wicks don't drown in their own melted stuff as some I've tried, etc.) I get the big ones in the jars with lid...seem pricey but really do last a very long time. I like Patricia's favorite but my personal fave is Hippie Chick (yeah, it smells like it sounds....like the old days.) LOL