Masterpiece

Flour

Flour plays a significant role in cookies because depending on its ratio, it helps the cookie stay its normal circle cookie form. Without it, it would just spread all over your baking sheet creating a big mess. Flour can make cookies chewy, crisp, or even crumbly. A substitute for flour are whole-grain flour which imparts a much healthier, and nutier flavor.

Sugar

Aside from adding sweetness, specifically white sugar helps the cookies spread resulting into a thin and crispy cookie. Brown sugar also plays a huge role in cookies because of the molasses. The molasses adds moisture because it's a slightly acidic, this causes the proteins in cookie dough to firm up faster, creating a chewier texture. Substitutes you can use are coconut-sugar, and honey for a more healthier, and cleaner cookie. 

Butter

Butter is important in a cookie recipe. When mixed into flour, fat coats some of the flour and protects it from the liquid. This process prevents from gluten developing, thus making the cookies more tender and not too overly chewy. Butter also contributes flavor. Substitutes for butter are margarine, coconut canola or olive oil.

Eggs

Eggs have protein and give moisture to a cookie. The liquid in eggs gives a cookie structure. Protein helps make cookies chewy. Substitutes for eggs can be applesauce and bananas.

Salt

Salt adds flavor Because we have sugar in this recipe we need salt to even it out creating a balance to the cookie. Salt also strengthen the protein in a dough, making cookies chewier. There are no substitutes for salt.

Leavens

In your traditional cookie recipe it calls for baking soda or baking powder. The difference in these two are baking soda is sodium-bicarbonate and when you heat sodium-bicarbonate you get something called sodium-carbonate which is a soapy, bitter taste and to balance that out you will need a acid. But if you are just using baking powder the acid is already in there so you're good to go.