Trust us: Adding a bit of salt to sweet treats makes them taste even better.
Adjust oven racks to upper-middle and lower-middle positions and heat oven to 350 degrees. Line both rimmed baking sheets with parchment paper.
In medium bowl, whisk together flour, baking soda, and baking powder.
In large bowl, whisk dark brown sugar and melted butter until smooth and no lumps remain, about 30 seconds. Add whole egg, egg yolk, and vanilla and whisk until well combined, about 30 seconds.
Add flour mixture to sugar mixture and use rubber spatula to stir until just combined and no dry flour is visible, about 1 minute.
Use oven mitts to remove baking sheets from oven (ask an adult for help). Place baking sheets on cooling racks.
If you look at recipes for sweets—like cookies, cakes, and even ice cream—they almost always include a small amount of salt. But when you eat those sweets, they don’t taste salty, do they? So why include the salt?
One of salt’s many superpowers is that it changes the way we perceive taste. Adding just a little salt—not enough to make something taste salty—can make food taste sweeter. Scientists only partially understand why this works. When you’re eating, your tastebuds send messages to your brain about the tastes they detect in your mouth. One theory is that salt blocks tastebuds from tasting bitterness. And if you taste less bitterness, your brain believes what you’re tasting is . . . sweeter!
When we baked these cookies, we tested some without any salt on top, and some with salt on top. Our tasters also noticed other flavor differences in the salted cookies—they tasted nuttier, and some tasters detected a caramel flavor. Can salt also bring out other flavors in food? Scientists say yes! However, they don’t totally understand how it works. Maybe you’ll be the scientist who figures it out!