Kimberly's response to my question above made me wonder what a large egg (the common US recipe size) meant here in Europe. Wiki has a page with charts about how much "egg" is in various sizes in various parts of the world.

I suppose if you had medium eggs in one part of the world and the recipe you're following is calling for large eggs comes from another continent, you might need to resort to the liquid ounces or grams listed on this page.
http://en.wikipedia.org/wiki/Chicken_egg_sizes

Yes, you make a good point. This is why professional bakers weigh ingredients (so it doesn't matter where they are in the world, their products will generally turn out the same). Weighing makes it very easy to quickly measure how many whole eggs, egg whites or egg yolks are required for a particular recipe/formula.

All of the recipes on our site call for large eggs (unless otherwise specified). Here in Canada, large eggs roughly weigh 50 grams (30 grams for the white and 20 grams for the yolk) excluding the shell. This is why bakers and cooks also have to have some solid math skills to scale recipes and do conversions. Cheers!

I'm making a double batch (BIG family, and they're all cookie hoarders) and adding about 8 tb. of cocoa powder. Does that sound about right? I just took a shot :P Also, I am not sure how packed the brown sugar is supposed to be. I'm just getting my mise en place ready right now, and I have it just slightly packed :P Anyway, thanks for this amazing recipe, can't wait to try it out! My mom has a good recipe, but they're never quite as chewy as I'd like them.

In baking, substituting gets trickier because formulas are designed so that the proportions of ingredients work harmoniously together (i.e. proportion of dry ingredients to wet ingredients, the amount of baking soda vs. the amount of acid in a recipe, etc.). It is too hard to say how they will turn out without trying it (you will likely need to decrease the quantity of flour). This drill down shows how to measure brown sugar. Rather than making tweaks with a double batch, I'd recommend trying it out on only 1 batch to see if you like the results. Cheers!

I ended up making them like I said above. I did two seperate batches, one that got cocoa and one that didn't. The ones without the cocoa were perfect, and the ones with it were really good, but a little hard :P I microwaved some and put it on ice cream and we still got a good desert out of it. Anyway, next time I'll take out some flour if I add cocoa :P The biggest reason I did that was the fear that I didn't have enough chocolate chips. But, ah well, trial and error. Delicious trial and error P: Thanks for the recipe guys! :) Will be making some more yummy stuff from the site this weekend.

Great job for trying! That's what we want to see - students getting in there and testing and tweaking to try things out for themselves. It's the best learning process. There's nothing wrong with harder cookies...especially when they have chocolate in them :-)

I've made these a few times now and the tops are always cracked kind of look like an oatmeal raisin cookie. What should I do different? that fleur de sel is incredible! the second time I made it I increased the salt x3 so I can really taste it with the chocolate. Unhealthy but I only made 6 that way.

Roll them into smooth balls prior to baking. Also make sure to test the internal temperature of your oven. It may be running too hot. Cheers!

The cookies tasted great. This is definatley a keeper. However, I was a little disappointed that the chocolate chips didn't melt. I actually cooked my first batched a little too long hoping to get the chips to melt a little but it didn't happen. Any thoughts?

I am not sure why the chocolate chips did not melt. Perhaps it was the type of chips you were using?

when i mix the melted butter and the two types of sugar together, they did not mix well and it was very grainy. My brown sugar actually formed into very sandy-like sugar balls.

Could the problem be the butter? because when melted and sit at room temperature for an hour it's still looks like oil (like someone's butter problem above)

I went ahead and mix anyway and then put it in the fridge for a bit to try to let it harden a bit.

Anyway can I go ahead and bake them or should i just make another batch?

also, when i mix the butter and the sugar, the color was SUPER dark. it was not pale brown like yours. What could have gone wrong? Is it because i used "dark brown sugar" instead of the paler one used in the video?

Thanks a lot. I can never seem to nail this recipe (sigh)

Do not worry Echo, the grains of sugar will not totally dissolve and they will a bit look grainy, especially if you have used a wooden spoon to mix, rather than the mixer (which is the method we now prefer). And yes, the color of the butter and sugar when mixed together will be darker, depending on the color of your sugar and whether or not you mixed by hand or by using a hand-mixer.

I am sure if you bake the batch you have they will turn out perfectly. And if not, then keep trying. At least your practice cookie are still delicious :-)

In previous comments people have asked about using 1 tablespoon of vaniilla. In the recipe that is currently posted only list 2 teaspoons of vanillia. Why the change when all the Rouxbe Staff verified 1 tablespoon and how great the cookie were? Just wondering.

I have made several batches of these cookies as listed and they are awesome. Thank you.

We changed the amount of vanilla to be a bit "everyone-friendly". If you really like the flavor of vanilla, by all means you can add a full tablespoon. Personally, over the last few years, I have found that I like a bit less vanilla in most things. I just like it to be a bit more subtle. Cheers!

I experimented with this recipe and found the following. I hope this helps anyone having problems. I enjoy thick, chewy cookies. I live in high altitude too.

I didn't modify the ingredients of the recipe any, just refined the technique. I just had to make sure my flour wasn't too "airy" so I didn't end up putting less flour in it then was needed. Many cookies lost their lives to get this information :-)

I researched the reason for melting the butter and found a good explanation about how the butter's emulsion breaks down creating more water for the gluten to form and therefore creating a chewier cookie. It doesn't seem to really matter if the butter is liquid or more solid after cooling except that a cooler butter makes it easier to cool in the fridge before cooking, which effects the thickness of the cookie (explained later). What works for me is melting in the microwave until it is just a liquid and then cooling the dish in ice water while frequently stirring the butter until it is the consistency of yogurt. I'm starting to believe that this also helps with making a thicker cookie too.

I cream the butter and sugar at high speed to incorporate more air in the dough. I also use a high quality 3x strength vanilla to give a higher quality taste. I prefer a little less chocolate chips in my dough than in the recipe, but I also enjoy mixing different types just for fun. I have to say the salt makes a big difference. I can't find fleur de sel here locally, so I have been using a course grind of a local salt here called "Redmond Real Salt." it is similar to Himalayan salt, except cheaper because it is mined nearby were I live, and it is sweeter. It is worth looking up on the Internet. The course texture of the salt made for little pin like points in the cookie that awakened the taste buds for a pleasantly sweet taste. Others couldn't tell what it was that made the difference, but I did.

I weigh my dough out to 2.5 ounces exactly. I find it looks better for presentation when you have big cookies that are the exact size except that I have to convince others I made them instead of buying them. Also, they seem to cook better and achieve a better thickness when they are bigger. smaller cookies just don't cook well. I get 15 cookies out of the recipe; that would be a dozen to give away and three extra for my little helpers and me.

Chilling the dough made the biggest difference with the thickness of the cookies. I chill them for about 45 minutes on the baking tray AFTER I form the dough (six cookies per sheet to give them room). I roll it in a ball and then press it into a cylindrical shape so it make a nice tall dough. My cookies cooked for different times and temperatures depending on how much the dough was chilled. less chilled dough cooked better at slightly higher temperature for less time while more chilled dough faired better with the 325 degree oven for about 14 minutes. I cooked them until the top just gets past the still-looking-raw stage. They end up looking like little domes when I remove them from the oven and then collapse to the proper thickness when they cool. I like the cookies when they have had a good few hours to a day to rest.

The following resulted in flat, crispier cookies for me: Too much butter (result of improperly measured flour), dough was not chilled enough, and not cooking them at the right temperature or cooking them for too long. I tested many batches with some fatalities, but eventually perfected it and received some very sincere compliments from many people. This is what has worked for me; I hope it helps others looking for help. Thanks to everyone in the forum with all their great information and ideas. Happy Baking!