I use dark brown sugar in my chocolate chip cookies and they're delish. I started by accident when I was out of light brown sugar, but I haven't looked back. It does make the cookies nice and moist in the center, and they get crisp on the edge. I don't make any adjustment to baking powder either. I would think blondies would taste good with brown sugar; I just wonder if blondies from the center of the tray will come out softer than desired (due to the increased moisture from the molasses in the sugar, and the decreased surface area for crisping, as compared to standard chocolate chip cookies). Still, I'd try it. Report back, please!

Absolutely! I often do. It makes them even more butterscotchy.

Molassesy. I like that--kind of like "sassy."

If you're terribly worried about the dark brown sugar becoming the overpowering flavor, you can cut it with plain white sugar, up to half and half.

Go right ahead! As Sadassa says, they'll be a bit darker because of the increased molasses. Also for that reason, if your recipe calls for baking soda, you might want to increase it by 1/4 teaspoon to fully neutralize the acid in the molasses. I suspect they'll be delicious!

yes, the flavor will be a little more molassesy, but should be delish!

yes, they will be a little darker and I think even tastier!