In a medium bowl, mix together flour, cocoa, salt, and baking soda.
In a large bowl, cream butter and sugars. Add eggs and beat. Stir in vanilla.
Add dry ingredients and mix well.
Stir in chocolate chips.
Drop mixture by rounded tablespoon onto ungreased baking sheet. Bake at 375 degrees for 10 minutes. Makes 3 – 3 1/2 dozen depending on how big you make the cookies.
Notes
If you used butter and the dough seems too soft, then put it in the refrigerator for an hour to firm it up.