Brown the butter in a saucepan, pour into a large bowl and allow it to cool to room temp.
Mix baking soda and water together and set aside.
Cream together butter, shortening and sugars.
Add eggs and vanilla, mix well.
Add the baking soda and water mixture.
Mix in salt and add flour one cup at a time, mixing well after each addition.
Stir in chocolate chips.
Spread batter in a greased jelly roll pan.
Bake at 350° F for 20-25 minutes. Do not overbake.