To make your cookies stay soft after cooling, there are a few adjustments you can make to your recipe:
Increase the fat: Adding more fat, such as butter or oil, to your recipe can help keep the cookies moist and soft. You can try increasing the amount of butter or using a combination of butter and oil.
Use brown sugar: Brown sugar has a higher moisture content compared to granulated sugar, which can help retain moisture in your cookies. Replace a portion or all of the granulated sugar in your recipe with brown sugar.
Add cornstarch: Adding a small amount of cornstarch to your cookie dough can help create a softer texture. About 1 to 2 tablespoons of cornstarch per batch of cookies should suffice.
Don't overmix the dough: Overmixing the dough can lead to tougher cookies. Mix the ingredients until they are just combined to prevent developing too much gluten, which can result in a denser texture.
Underbake slightly: Take the cookies out of the oven just before they look fully done. They will continue to cook and set as they cool on the baking sheet, resulting in a softer texture.
By incorporating these adjustments, you should be able to achieve cookies that remain soft and chewy even after they cool down.