The Great Cookie Experiment

Sometimes, I take things a little too far.  The length of this post is a good example of that.  Last week, I got a craving for chocolate chip cookies.  I suppose I could've gone to the store, or maybe the coffee shop down the street, and just bought one.  That's probably what a normal person would do.  But I wanted a real, homemade chocolate chip cookie.  And then I realized, I don't really have a go-to chocolate chip cookie recipe.  It's by far my favorite type of cookie so, what gives?

To remedy this anomaly, I set out to create my very own chocolate chip recipe.  When I was little, chocolate chip cookies were one of the first things I remember being allowed to bake by myself.  Not knowing any better, I just followed the recipe on the bag of chocolate chips.  The one deviation from the chocolate chip bag recipe was a little piece of advice from my mom: always refrigerate the dough for "a few hours" before baking.  But ... why?

Well, for starters, if your butter is too warm (e.g. room temp) when you put the cookies in the oven, they'll spread out before they've had time to set.  That results in a thin, rubbery mess of a cookie that probably melds into all the other cookies to become a brown blob on your baking sheet.  We've all experienced these disasters and if you're anything like me, you probably ate the cookie blob mess anyway.  But there's an easy fix to this.  A few hours in the fridge and the problem is solved.  You see, the colder the butter, the longer it takes to melt.  The longer it takes to melt, the more time the cookies have to set, which means you get a nice fluffy cookie not a scrawny anorexic cookie.

Another reason chilling is good for the dough is moisture absorption.  If you leave your cookie dough in the fridge, even just for an hour, you'll notice the dough firm up and start to get a little crumbly.  It'll still shape up fine if you form it into a ball but just scooping it with a spoon is no good.  The dry ingredients need some time to relax and soak up the moisture in the cookie, particularly the eggs.  The more it soaks up, the crumbly it gets, and crumbly dough makes for a lovely, chewy-but-not-rubbery texture in the baked cookie.  So the longer you leave the dough in the fridge, the chewier the cookie will be.

The last reason -my own personal theory- is related to the chemistry of pie dough.  When making pie dough, you want to use cold ingredients - cold water, cold butter, etc.  Like straight-from-the-fridge cold, none of this room temp business.  As the crazy cold butter melts in the oven, it releases steam.  The steam gets trapped within the dough as it bakes, resulting in a pie crust that's airy and flaky.  My theory for cookies is that the same thing happens in cookies and results in more moisture and lightness despite a dry, crumbly dough.  The steam released by the butter on the outer edges of the cookie will evaporate, making the outside a little crisp.  But the steam on the inside of the cookie has nowhere to go.  Instead, it gets trapped in the cookie, adding moisture and a bit of lightness.

Because I tend to take things too far in a totally nerdy way, I couldn't just bake some cookies.  I had to create an experiment to test my theory - the longer the dough chills in the fridge, the better the cookies will be.  I made a basic cookie dough (with a few twists) and baked three different batches over the span of 48 hours - a 4-Hour Cookie, a 28-Hour Cookie, and a 48-Hour Cookie.  Let me tell ya, staring at delicious cookie dough every time I opened the fridge for a full 48 hours took extreme will power.  I felt like a crack whore forced to babysit -but not sample- my dealer's stash.  All in the name of science.

My hypothesis was that the 48-Hour Cookie would be the best cookie in both texture and flavor.  If my assumptions were correct, this cookie would be moist and chewy on the inside and slightly crisp on the outside, with a variation in color from the edge to the center.  Because the flavors would have a longer time to get all friendly with each other, the brown sugar and butter flavors should be much richer and more distinguished in the 48-Hour Cookie.

All three batches were baked for the same amount of time, at the same temperature.  The only variable was the chill time for each batch.  So, did the baking gods prove me wrong?

The 4-Hour Cookie
It's a good cookie.  Just fine (said in a slightly higher pitched voice).  The texture was chewy without being rubbery.  There was plenty of time for the dough to set so it puffed up nicely.  The edges and bottom of the cookie were slightly browned but the rest of the cookie was an even light golden color.  The chocolate chips definitely dominated as the main flavor but there wasn't really much depth to the cookie.  There's nothing wrong with this cookie, per se, but there's also nothing special about it.

The verdict: a good solid cookie.

The 28-Hour Cookie
I actually meant for this to be 24 hours but I got home later than expected on Friday.  It's okay, though, because something beautiful happened for this cookie.  The Boyfriend even noticed a difference.  It was much more moist than the 4-Hour cookie.  And chewier, too.  So delightfully chewy.  The chocolate chips were nicely complemented by a subtle brown butter flavor and the sea salt was more distinguishable (it was non-existent in the 4-Hour Cookie).  In fact, this cookie has me convinced that every batch of chocolate chip cookie dough should rest in the fridge for at least 24 hours before baking.  Otherwise, you're just doing yourself an injustice.

The verdict: a pretty darn delicious cookie.

The 48-Hour Cookie
I had high expectations for this one.  I thought it would blow my mind.  I thought it would rock my world, shiver my timbers, melt my butter, and float my boat.  Not quite.

Now don't get me wrong, it was a freaking delicious cookie.  The flavors really came together with the extra chill time, which resulted in an a caramel flavor complementing the chocolate chips.  The butter and sugar really loved having that extra time to get to know each other.  But the texture of the 28-Hour Cookie was better in my opinion.  I much prefer a cookie that's crisp on the edges but soft and chewy on the inside.  The 48-Hour Cookie was mostly chewy from edge to edge with not much variation.  (A couple more minutes in the oven might have helped this but I really wanted to keep all three batches to the same cooking time.)

Basically, this cookie was equally delicious as the 28-Hour Cookie but the extra day of chill time cost it some points.

The verdict: a pretty darn delicious cookie, too, but not worth the extra day of waiting

So, all in all, I was right and wrong.  The flavors were definitely better in the 48-Hour Cookie but the texture wasn't what I expected.  For me, that trade off isn't worth the extra day of waiting before I can eat those yummy things.  If you prefer chewy cookies, though, then the 48-Hour Cookie is absolutely the one for you.  But don't take my word for it.  Bake up a batch using the recipe below and see for yourself (just stay away from the fridge while the dough chills...)!

What You Need:
2 and 1/2 cups flour
1 c. brown sugar
3/4 c. granulated sugar
2 sticks of butter (1 cup), room temperature
2 eggs
1/2 tsp. baking soda
1/2 tsp. baking powder
1 tbsp. vanilla extract
1/4 tsp. cinnamon
1 tsp. coarse sea salt
1 bag semi-sweet chocolate chips

What You Do:
1. In a medium/large mixing bowl, cream together the butter and sugars until light and fluffy, about 3 minutes.

2. While that's mixing, sift together the dry ingredients (flour, baking powder, baking soda, salt, and cinnamon) in a separate bowl.

3. Once the butter and sugar get nice and fluffy, add in the eggs and vanilla extract and mix until fully combined.

4. Slowly add in the dry ingredients and when it's all nice and mixed up, fold in the chocolate chips.  Cover with plastic wrap and refrigerate for up to 48 hours, depending on what kind of cookie you want.

5. When you're ready to bake, preheat the oven to 350 and line your baking sheet with parchment paper.  Scoop a spoonful of dough and gently shape into a ball roughly the size of a golf ball.  Place dough balls on the cookie sheet at least an inch apart and bake for 10-12 minutes, or until the edges just start to become golden.  Remove from the oven and let them couple for a few minutes on the baking sheet.  When they're cool enough to handle easily, move to a wire rack to cool completely.

Note: The center of the cookies might look unfinished when you first take them out but by the time the cookies cool completely, they'll be perfect.  If you prefer a more crispy/less chewy cookie, bake for an extra couple of minutes.   Also, this recipe makes about 36 cookies.  We ate them all before I could take pictures (which is why you only see 2 in most of these photos).



  1. I only wish I had been there to taste test for you. I will have to try to be patient enough to keep my dough in the fridge for 24 hours.


  2. Yum!! I will have to try your recipe for sure! I recently made the "thick and chewy chocolate chip cookies" from America's Test Kitchen cookbook because I have been in search of the perfect recipe for years and years to little avail... I was skeptical at first but SO delighted with the results - very chewy and perfectly shaped (uses melted and cooled butter!) Anyways, I love reading your blog - your photos and posts are always so lovely. Check out mine sometime! (it's much more fledgling however!)http://lavenderspoon.blogspot.com/

  3. This. Is. Awesome!
    Chocolate chip cookies are my favorite and something I grew up on. I'm talking we had them on hand at ALL times. I can honestly remember 2 times during my childhood that we were left craving a cookie.
    I love that you turned it into an adult science project.

  4. OMG, these look so delicious and I love how you talked about all the different stages and everything about these cookies. That's cool they're the first thing you baked as a kid.


  5. this is awesome! i've never chilled my dough and love my cookies but i'm going to try the 24 hour method and see how it turns out.

  6. FAR too many photos of cookies in this post - I am way too hungry now! :P

  7. 1) "But don't take my word for it" -- so reminds me of Reading Rainbow :-)

    2) As a science teacher, I heartily approve of your use of hypothesis, your adherence to the scientific method (same baking time and everything!), and your overall experiment. I have only one little qualm, and that's with the use of your word theory. You used it well, colloquially speaking, but the scientific standard for a theory is a high bar. You'd have to do a lot of cookie experiments to reach the level of rigor needed for a theory. (old blog post about this: http://penn.typepad.com/penn/2004/11/the_theory_of_i.html)

    Anyway, overall awesome :-) Thank you for sharing! I really want to try the recipe. I have never been patient enough to wait, but I'll have to try it next time we make cookies.

  8. Uhh, best experiment ever? This is one of my favourite posts that you've done and I'm bookmarking it for future reference when I bake chocolate chip cookies, which after looking at your pictures may just be later today.

    I've also heard that storing cookies with a slice of bread will keep the cookies moist.

  9. Now I want a cookie! Thanks for posting this. I'm going to take your advice and the 28 hour cookie!!

  10. are you seriously doing this to me right now???!!! i just started a cleanse today and this is pure torture! ;) oh, my goodness...i know exactly what me reward will be once this cleanse is finished ;) XO brynn

  11. I usually leave it in the fridge for at least 8 hours. I read that the maximum you should leave the dough in the fridge is 72 hours. That's helpful when you don't want to bake the cookies all at once!

    I'll have to try your recipe soon! I love finding new recipes for cookies!

  12. I'm not even sure I could wait the 24 hours!
    Lexi @ Glitter, Inc.


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