What makes a cookie chewy - effects of ingredients question

Something I've always wanted to know . . . if you have a recipe for a cookie or a bar, how do you modify it to make it more dense and chewy, yet still soft?

This question came up twice:

•once when I was trying to figure out how to make what were called "Ranger Bars" that were available when I was a lad - flat square shaped cookies about 1/4" - 3/8" thick, but very soft and chewy.

•and lately a project to bake a Clif type bar.

I've found recipes for these, but the results are never dense and chewy, in my opinon, but too light, dry and cakelike.
(I might be using the wrong terminology here - I'm after the consistency/texture of a Clif bar - the opposite of crumbly.)

. . . all of which leads to My Question:

If the amount of flour is kept constant, do I add more/less :  fat, sugar, eggs, leavening, etc?

Anyone know what controls to this attribute?

Ok, thanks everyone . . . this is all very helpful.

I'm trying my Clif Bar recipe tonight - see how chewy/flavorful that comes out.

Kent

Returning to my question I posted here a few years ago . . .

Later on I found a great article on Sunset.com :

The perfect chocolate chip cookie . . . where a paragraph discusses :

What makes cookies soft and chewy?

High moisture content does; so the recipe, baking time, and temperature must be adjusted to retain moisture.

Binding the water in butter, eggs, and brown sugar (it contains molasses, which is 10 percent water) with flour slows its evaporation. The dough needs a little extra flour, which makes it stiffer. The stiff dough spreads less, less liquid evaporates, and the cookies are thicker.

Mass also helps cookies stay moist--big dollops of dough make softer and chewier cookies than tiny spoonfuls of dough. Bake these thick cookies for a shorter time at a high temperature to firm them quickly and minimize spreading. Most important, don't bake them too long--remove from the oven when the cookie rim is brown and at least 1/3 of the center top remains pale. The cooked centers will be soft.

What makes a cookie crisp or crunchy?

Reducing the amount of ingredients that hold moisture--flour, egg, and brown sugar--makes it easy for liquid to evaporate, producing crisp cookies.

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So to make a cookie more chewy, from all the info that I've found (including here) . . . . if the amount of flour is kept constant, then I gather you need proportionally . . .  :
(And I am not a professional or expert cook by any means, just trying to make sense out of what I've read. If anyone knows better please correct me.)
 

• more sugar, especially brown sugar.  (this is the one thing I notice in all the "chewy" recipes - they all have more brown sugar)
• more eggs (?), or at least extra egg yolk. It seems that more of whole egg will make the cookies both chewy and thicker.
• more gluten development
• slightly less liquid  (liquid makes the cookies spread)
  However - and this is important - a primary objective is to have the dough retain moisture. But the way to do it is not to just add liquid itself.
• less baking time but higher baking temp
• melting the butter (adding this from the "chocotuile" suggestion below, and from the "The Perfect Chocolate Chip Cookie" article/recipe cited below.

• less fat (although I see some recipes using slightly more. In general more fat creates more internal heat which drives out the moisture, and it also causes the cookies to spread, making them thinner and crispier. )

Maybe someone reading this can clear up some of the ambiguities.

Also my friend Kelly says midway through baking you can take the cookies out of the oven and give them a smack to drive the air out of them.

Not sure how the cookies feel about that.

Can't leave my post alone. . . .

So someone gave me a print copy of Cooks Illustrated "The Perfect Chocolate Chip Cookie" from the May 2009 issue, raving about their results.

Charles Kelsey did a bunch of experiments on this subject and basically came up with the same list as I posted just above.

From the two eggs, he took out one egg's whites, but used only that egg's yolk.

In addition, he melted the butter, explaining that it exposes more of the liquid in the butter to the mix.

(He also browned some of the butter for more or a nutty flavor.)

And he used more dough for each cookie

Still, my hunch is that the major factor is the increased brown sugar.

The print article is three pages of very densely printed text, while the online article is very much abridged, here :

http://www.cooksillustrated.com/recipes/article.asp?docid=19504