Too Long in the Oven

• One of the most common mistakes made when baking cookies is to over-bake them. This causes the edges to become crisp and the entire cookie to harden as it cools. Too low an oven temperature also causes the cookies to spread out further, making them thin and crisp. Check your cookies often, as baking time varies depending on your oven. Remove the cookies when the edges are set and the bottoms are lightly browned, while they are still soft in the center. Cake-like cookies, such as molasses cookies, should feel soft but spring back when touched lightly in the center.

Mixing Magic

• How you mix your cookie dough also affects the outcome of your cookies. Creaming the sugar and shortening with an electric mixer until they are fluffy introduces air to the batter. This causes the cookie dough to spread out during cooking and creates a crisper cookie. Hand mixing the sugar and shortening introduces less air, resulting in chewier and denser cookies.

Balance the Ingredients

• The ratio of shortening and liquids in your cookie recipe also affects the outcome of your cookies. If your cookies come out hard and crunchy, you may be able to correct that by altering the ingredients. For soft cake-like cookies, try adding more liquid to your recipe. Recipes with a high amount of liquids and lower amounts of both sugar and fats produce soft cookies. These recipes often contain eggs. For soft, chewy cookies, try reducing the fats in your recipe. Low-fat cookie recipes that contain high amounts of both liquids and sugar with low amounts of fat produce chewy cookies.

Skip the Extra Flour

• Adding too much flour to your dough during handling can also lead to crisp or hard cookies. If you are making rolled cookies, avoid kneading the dough with flour unless directed to do so -- and observe the proper thickness. Introducing flour during handling or rolling your cookies too thin causes your cookies to bake up crisp or hard. Lightly greasing your hands allows you to handle sticky dough without introducing additional flour while forming the cookies.