Adding Liquids to Cookies

This week I made butter cookies with various liquids added. I tried adding one egg yolk, one egg white, 1.5 Tbs water, and 1.5 Tbs milk. The photo of cookies spread out shows five columns, with each column in turn containing cookies with:

- no added liquid
- one egg yolk
- one egg white
- 1.5 Tbs water
- 1.5 Tbs milk

The photo of the stack of cookies shows the same cookies stacked in order, with the cookies with no added liquid on top and the cookies with milk added on bottom. All these cookies were baked on the Wilton pan.

The spread of cookies shows well how the various liquids affected spreading of the cookies. The egg yolk and white added no spreading. The water led to a good deal of spreading. The milk caused an intermediate amount.

All the cookies were taken from batches that were just at the calibration point, i.e. just crisp when cooled to near room temperature. It is easy to see how whitish the cookies with egg yolk or white are - they were baked before any touch of browning occurred. The cookies with water were likewise baked before there was any browning, but they spread so much that one can actually see the brown table just slightly through them, so they appear a little darker. The cookies with milk were actually slightly browned around the edges, though it is difficult to see in the photo.

The photo with stacked cookies shows how much thicker the cookies with egg yolk or white were than cookies with no liquid. The three on top had no liquid, and the six immediately below them had egg yolk or egg white. The gas bubbles were smaller in cookies with egg proteins than in cookies without any liquid - I mentioned that before. That helped the cookies with egg yolk or white retain the miniscule chambers of gas that formed while they were baking. The photo doesn't do a good job of showing how thin the cookies with water and milk were, because of their angle. Those cookies were actually thinner than the cookies with no liquid. The gas bubbles were fairly large again in those cookies, so they both spread and lost the air in them. When cookies spread they have to get thinner to cover the same area, and if they also lose much of their enclosed gas bubbles, they get very flat. The cookies with water and milk were very much like wafers, they were so thin.

The gas within the cookies with eggs were very well dispersed through the cookies. Those cookies were crispy but almost soft, similar to pecan sandies or Oriental almond cookies, though not quite as thick. The cookies with water or milk weren't very crumbly at all. They tended to be somewhat crunchy, though I shouldn't overstate it as though they were unpleasantly hard. The cookies with water or milk were actually so thin that a few of them showed small signs of pitting or holes through them.

Not surprisingly, the cookies with water added had the same flavor as the cookies with no liquid added. The cookies with milk were very subtly different. I thought maybe I could actually taste the milk flavor, but it was hard to pull that out with all the butter and sugar. I could definitely taste the eggs in the cookies containing them. The cookies with yolk versus white were noticeably different in taste.

The cookies with milk and egg white weren't as sweet, or the flavors hid the sweetness, though they all had exactly the same amount of sugar.

My favorite cookies by taste were:

no liquid or water
egg yolk
milk
egg white

Because of the great texture, I think the cookies with an egg yolk come out on top for me, between these variations.

In every case, the cookies on the Williams-Sonoma GoldTouch Commercial Cookie Sheet were superior to the cookies baked on the Wilton pan. The cookies with egg yolks were pretty decent even on the Wilton pan, but I'm still looking for a method that makes them great on the Wilton pan.

I think I next want to look at the effect the baking powder is having on these cookies. If large gas bubbles are sometimes causing problems, maybe they would be improved with less or no baking powder. Or, because they are so flat, with more baking powder. Who knows?

We soon will - know, that is - after I get a chance to try it. I do that with and without egg yolks, using half the baking powder (a quarter teaspoon for the entire recipe) and no baking powder, and I'll also try it with a full teaspoon of baking powder. Should be interesting!