The reason why your cookies are puffy and cakey is a result of using too many eggs, using the wrong type of flour or even using too much baking powder or baking soda or when you over mix the cookie dough.
What makes a cookie puffy is over mixing or over whipping the cookie dough and or using too much baking powder or too much baking soda or using the incorrect type of flour.
Cake flour absorbs less water which leads to steam buildup and puffiness so make sure you're using the correct flour such as all purpose flour.
Whipping too much air into the dough leads to a fluffy cookie so you want to make sure to not over whip or over mix the cookie dough.
To make your cookies fluffier instead of flat use cold butter, chill the dough and adjust the baking powder or soda and sugar ratios.
Also use baking powder instead of baking soda as baking powder tends to create more lift and a fluffier texture than baking soda that can lead to a flatter cookie.
And chilling the dough before baking the cookies allows the gluten to relax and the fat to firm up and prevent excessive spreading and promoting a fluffier texture.
Use cold and not melted butter as cold butter creates tiny air pockets which expand during baking and results in a fluffier texture.
And cream the butter and sugar thoroughly as it helps to incorporate air into the cookie dough and is crucial for a light and fluffy texture.
The reason why cookies turn out puffy is because you're either over mixing the cookie dough which incorporates too much air into the dough or when you bake the cookies at too high of a temperature which causes the cookies to rise too quickly and then deflate and lead to puffy cookies.
Over mixing the cookie dough develops the gluten in the flour and leads to a tough and chewy and potentially puffy texture of the cookie.
The over mixing also incorporates too much air and causes the cookies to rise excessively and then fall.
To prevent puffy cookies you should mix the dough just until the ingredients are combined.
Also make sure the oven is set to the proper temperature which is often 350 F.
An oven that is too hot can cause the edges of the cookies to cook faster than the center and lead to a puffy appearance as the inside of the cookies expand before they set.
Warm cookie dough can also spread excessively during baking which leads to a flat or puffy appearance to your cookies.
Chilling the cookie dough before baking also helps to maintain the cookies shape.
Also baking the cookies on a foil lined baking sheet can also lead to thin, flat cookies so it's best to use a baking sheet lined with parchment paper or a silicone mat.
When you add too much egg to cookies it can cause the cookies to become cakey, spongy and have a flat texture.
The excess moisture from the extra eggs can disrupt the balance of the cookie recipe and lead to a less desirable cookie.
Eggs contribute the moisture needed to the cookie dough but adding too many eggs can make the cookie dough too wet, which leads to the cookies spreading out, flat and having a cakey texture.
The cookie dough also can become sticky and difficult to work with as a result of the increased moisture from the extra eggs.
And if you find that your cookies are coming out cakey you can add a bit more flour to the cookie dough to compensate for the extra moisture.
What makes cookies chewy vs cakey is the amount of sugar used and the amount of baking powder or soda or the amount of eggs used.
A higher sugar to flour ratio leads to more moisture and chewy cookies and using the proper amount of baking powder or baking soda and using the proper amount of eggs.
Cakey cookies are often a result of too much baking powder or too much baking soda or too many eggs which result in a fluffy and cake like texture to the cookies.
The secret to chewy cookies is to use an extra egg yolk and cornstarch and more brown sugar than white sugar.
Using more brown sugar than white sugar when making cookies results in a softer, chewy and moisture cookie.
Using an extra egg yolk increases the chewiness of the cookies.
Also rolling the cookie dough balls to be tall and lumpy instead of wide and smooth will give your cookies the bakery style textured thickness.
To make cookies chewy without cornstarch.
Go heavy on brown sugar. It has more moisture than its granulated counterpart, which means the cookie comes out less crispy.
Choose margarine or shortening instead of butter.
Use baking powder instead of baking soda.
Rest your dough.
Shorten baking time.
The ingredients you use and how you shape your cookies both play an important role in whether your cookies turn out crispy or chewy.
The type of flour and sugar you use, if your cookie dough contains eggs, and whether you use melted or softened butter all factor into the crispy-chewy equation, too.
Cookies that are dense and chewy incorporate more moisture into the batter.
This can be achieved by making substitutions with wet and dry ingredients, or even just changing the way you incorporate certain ingredients.