If your cookies are coming out with a cake-like texture despite paying attention to how much you mixed the egg and butter, there could be a few other factors contributing to this issue. Here are some possible reasons and solutions:
Flour: The amount of flour used in the cookie dough can greatly affect the texture. Using too much flour can result in a drier and more cake-like texture. Make sure you are accurately measuring the flour and consider using a kitchen scale for precise measurements.
Leavening agents: The presence of leavening agents such as baking powder or baking soda can cause cookies to rise more and have a cake-like texture. Double-check your recipe to ensure you're using the correct amount of leavening agents.
Sugar: The ratio of sugar to other ingredients can also impact the texture. Too much sugar can lead to a cakier texture. Reduce the sugar amount if you find your cookies are too cake-like.
Butter temperature: The temperature of the butter can affect the texture of the cookies. Using softened butter, rather than melted or cold butter, will generally result in a chewier cookie. Softened butter incorporates more air during mixing, leading to a different texture.
Resting time: Letting the cookie dough rest in the refrigerator for at least 30 minutes before baking can help improve the texture. Resting allows the ingredients to hydrate fully and helps the flavors meld together.
Overmixing: While you mentioned that you paid attention to how much you mixed the egg and butter, it's essential to avoid overmixing the entire dough. Overmixing can develop more gluten, resulting in a denser, cake-like texture. Mix the dough just until the ingredients are combined.
Baking time and temperature: Make sure you are baking the cookies at the correct temperature and for the appropriate time. Overbaking can dry out the cookies and give them a cakey texture. Adjust the baking time as needed to achieve the desired texture.
Use of cake flour: Some recipes call for cake flour instead of all-purpose flour. Cake flour has less protein, which can lead to a softer and more tender texture. Double-check your recipe to see if it specifies cake flour.
Egg size: Sometimes, using large eggs instead of medium-sized eggs can result in a cake-like texture. Check your recipe and use the egg size specified.
Oven calibration: Ensure that your oven is calibrated correctly to the right temperature. An oven that runs too hot might cause the cookies to puff up and become cakey.
Try adjusting one or more of these factors, and you should be able to achieve the desired cookie texture. Baking can sometimes involve a bit of trial and error, so don't be discouraged if it takes a few attempts to get your cookies just right!