Monday, October 13, 2014 – I’ve made a lot of chocolate chip cookies in my lifetime. (Well, mostly in the last 6 years.) But I’ve never made peanut butter cookies before. But then my friend [redacted] asked me to bake peanut butter cookies for her birthday. So I thought, what the heck, why not?
The first thing I did was look at peanut butter cookie recipes online to get a sense of what I was doing. For the most part, they were pretty consistent. The next thing I did was derive the recipe from first princples. After quick research (mainly looking at the back of a jar of peanut butter), I figured out that peanut is about half fat. Most recipes use equal amounts butter and peanut butter, so if peanut butter is half fat, I’d be increasing the fat content by 1.5x. So I figured increase the sugar and the flour to compensate. (Eggs don’t matter that much.)
The first thing I noticed was that my “derived” recipe had way more flour than the online recipes. And I thought that was odd, because if we have more fat, we need more flour to balance it out. Also, peanut butter cookies are traditionally more on the crunchy side, so having more flour would give the cookies the extra structural integrity they needed. Plus, when I creamed the butter and the peanut butter together with the sugar, the cookie dough was so soft that I thought I’d need extra flour anyway.
I was wrong. I don’t know what it is about peanut butter cookies, but after adding the 1.5x flour, the cookie dough hardened up super fast. Next time, I should use less flour. (The cookies still turned out great, though.)
I don’t know why peanut butter cookies are traditionally crimped with a fork. A quick internet search suggestions three reasons. One, it’s to flatten the cookies to help them bake better. (This one’s a lie. You don’t need a fork to flatten cookie dough.) Two, it’s to help people identify the cookies by sight. (Makes sense. If all peanut butter cookies are crimped with a fork, that makes them easily recognizable.) Three, tradition. (A cop-out answer, but an accurate one.) I decided to crimp mine anyway just because.
Because of the extra flour content in my cookies, my cookies didn’t melt much (if at all) and mostly stayed in their original shape and thickness. So I had nice thick peanut butter cookies with the crimp marks still visible.
When I first took the cookies out of the oven, the cookies were still soft in the middle. But after letting them “cool” for about 10 minutes, they were nice and dense in the middle. (Probably a combination of proper cooling and carry-over cooking.) And the outer edges of the cookie were nice and crispy like they should be.
As for flavor? The cookies tasted like peanut butter. And I used chunky peanut butter, so they also tasted like peanuts. Also, my kitchen now smells like peanut butter. I think this one’s a success.
Bonus: How to measure peanut butter. My cooking class suggested liquid measuring cup filled to about 1 cup water, then adding peanut butter until the water rises to whatever amount you need (let’s say 1.5 cups). So now you have 1/2 cup of peanut butter.
But then I realized it makes more sense to have equal weight butter and peanut butter and not equal volume. One stick of butter is 4 oz, so the next time you need peanut butter, just weigh out 4 oz (roughly 113g).