Eggs play several roles in baking brownies. They add liquid to the recipe and help strengthen the finished product so that it holds together. They also provide leavening by trapping air inside the brownie. Egg yolks also help keep baked goods from drying out. According to Baking 911, their lecithin content helps emulsify fats and liquids into a harmonious whole. Applesauce can also play some of these roles, adding liquid and helping to bind the brownies together, but it cannot emulsify fats or leaven significantly.

You can substitute ¼ cup of applesauce for each egg in your brownie recipe. People for the Ethical Treatment of Animals' egg replacement guide recommends using an extra ½ teaspoon of baking powder to make up for the loss of leavening power. This reduces the risk of damp, heavy brownies that fail to cook all the way through.

Fruit purees such as applesauce tend to change the properties of brownie batter. For instance, you may need to reduce the baking temperature by about 25 degrees Fahrenheit to prevent burning. The lower fat content of brownies that contain applesauce makes them cook more quickly. If you use sweetened applesauce, compensate by reducing the brownies' sugar content by 1 to 2 tablespoons.

Applesauce cannot act as a direct replacement for eggs in brownies. Baked goods made with this ingredient tend to be slightly denser and more moist than those made with eggs. The applesauce also contributes a noticeable fruity flavor in many recipes. Consider using more chocolate to cover this taste or add the applesauce to brownies that already contain fruit. Raspberry-chocolate and cherry-chocolate brownies work well with this type of substitution.