Here’s the one thing nobody tells you: dark brown sugar is slightly more moist than light brown sugar. It clumps together like a grumpy cat that doesn’t want to be measured. Light brown sugar is more easygoing, like a golden retriever.
If you’re swapping, just pack the dark sugar firmly into your measuring cup—or better yet, weigh it. A little extra moisture can make your cookies chewier (good) or your cake gummier (bad). For most recipes, it’s a non-issue.
