Can anyone tell me what the difference is between Light Brown sugar vs Dark brown sugar used in recipes? I need to make some cookies tonight and the store only had dark brown sugar. I am just making some choc chip and a sugar cookie.

From what info I can find the only difference is the amound of molasses in the sugars. Dark Brown Sugar has more, so it will have a stronger molasses flavor to it. Dark brown sugar may have a bit more moisture to it, but shouldn't make a difference in your cookies.

HTH

I think the dark brown just has more molasas. I personally only use dark brown because it makes my chocolate chip and raisin cookies darker and softer. I think it may make your sugar cookies too dark

Both types of brown sugar are a mixture of granulated sugars and molasses, with dark brown sugar containing more molasses than light brown sugar. Light brown sugar has a delicate flavor while dark brown sugar has a stronger more intense molasses flavor. They can be used interchangeably depending on your personal preference.

Answer found here.

Good Luck.