Chewy or crisp cookies
Brown sugar carries molasses, which holds water, so cookies stay moist and chewy. White sugar holds less water and melts into the dough as it heats, so the cookie spreads thinner and dries into crisp edges.
Butter and yolks change the chew too
Melted butter skips the creaming step, so less air gets trapped and the bite is denser and chewier. An extra yolk adds fat and emulsifier without the white's water. Skip the raw dough, since raw flour and eggs can carry germs.
Test yourself
Questions from the interactive lesson, with the answer and the why.
You want chewy chocolate chip cookies. Which sugar swap helps most?
More brown sugar and less white. Molasses holds water, so the cookie keeps a soft, chewy center.
True or false: Baking cookies longer at the same temperature dries them out and makes them crisper.
True. More bake time drives off more moisture, so the cookie gets crisper, not chewier.
What went wrong? You want chewy cookies, but you use all white sugar and bake a few minutes extra. They come out thin and crisp.
White sugar and a long bake dried the cookie out. White sugar holds less water than brown, and baking longer drives off the rest.
Fill the blank: The molasses in brown sugar holds on to water, which keeps cookies ___.
The molasses in brown sugar holds on to water, which keeps cookies chewy. Retained moisture keeps the center soft and bendy.
Why pull cookies when the edges are set but the centers look slightly underdone?
Heat in the pan keeps cooking the centers as they cool. Carryover heat sets the middle gently and keeps it soft.