I prefer cookies that are moist instead of crisp. Someone once told me that to get a moister cookie, one should increase the amount of brown sugar and decrease the amount of white sugar. Will that work? I don’t want to ruin an entire batch by trying this!

Brown sugar does have more moisture in it than white, so that tip is correct insofar as it goes. But that’s not the whole story, not by a long shot. As with any other kind of baking, there are many variables that will affect the final outcome of your product.

What kind of cookies are you making? Any good cookie recipe should have some sort of description of the end result, as they can vary so incredibly much. Meringues can be crunchy or soft, brownies can be fudgy or cakelike, peanut butter cookies can be soft or crisp. Unless you’re a crackerjack baker, you won’t know from the list of ingredients which it will be. So read those descriptions.

Let’s start with the assumption that you’re using a recipe for a particular kind of cookie that you know should be soft (or moist, to use your word), like a molasses cookie. In our house, those are called “quiet” cookies because Grandma wouldn’t know anyone was helping himself to one – they don’t make a sound when you filch one and bite into it.

Already you anticipate from the name that they’re going to be soft, because of the molasses. Plenty of moisture there — brown sugar is nothing more than sugar with some of the molasses left in it. But I’ve made them using Grandma’s recipe, and they came out crisp! What happened?

I didn’t follow the recipe exactly. It calls for shortening; I used butter. Shortening is 100% fat; regular butter from the store is only about 80% fat and 20% water and milk solids. You’re supposed to chill the dough before forming it into balls. I didn’t. You’re supposed to roll them in sugar – right, I didn’t do that, either (although I think that omission was minor.) This was taking place in a vacation rental, so there was no way to know if the oven was accurate; and to top it off, it was a hot day and I was in a hurry. Oh, and the cookie sheets were those disposable aluminum ones. Those babies spread all over the place, and became crispy-crunchy as they cooled off. It was, as my daughter would say, a major fail.

Here’s another example. A friend was making chocolate chip cookies in her stand mixer. As I watched her, she put in the butter, sugar, and eggs, and turned it on. “What are you doing?” I couldn’t stop myself from exclaiming (I try to refrain from commenting on people’s cooking unless I know they won’t mind.) I explained to her the importance of properly creaming the butter and sugar to aerate them before adding the eggs. She never knew there was a reason to add the ingredients in stages.

When it came time to bake them, she wasn’t very precise about portioning out the dough. I pointed out (by this time, I had permission to do some instructing) that they wouldn’t bake evenly if they varied too much in size. She began forming them more carefully.

As the first batch came out, she immediately began removing them from the baking sheets. Whoa, wait! Let them cool off enough to firm up a bit, or they’ll drape on the cooling rack. And don’t reuse the baking sheet until it’s completely cooled off, either, or the heat of it will cause the next batch of dough to start spreading before it goes in the oven. That batch of cookies will run into each other, becoming misshapen, and be crispy rather than soft.

Well, she said she learned something, and actually took pictures for my files of the results. I’m sure the folks at the potluck still enjoyed them, but they were far from picture-perfect or texture-perfect.

As you can see, to change a cookie’s texture can require more than substituting one ingredient. The type and amount of butter, sweetener, flour, eggs (if any) and/or raising agent matters; the mixing method, temperature of the dough and the oven, size of cookie, type of baking sheet, and length of baking time are all factors. If the recipe you’re following is supposed to yield a moist cookie and you’re disappointed with the results you’re getting, I’d look at other factors first. If, on the other hand, you’re trying to tweak a recipe that is supposed to yield a crisper cookie than you like, I suggest looking for another recipe.