Preheat the oven to 375 degrees F.
In a mixing bowl beat the shortening and butter with an electric mixer on medium to high speed for 30 seconds. Add 1 1/4 cups of the flour and the brown sugar and beat until thoroughly combined. Add the eggs, 1 at a time, and mix until incorporated. Add the vanilla and baking soda. Beat in the remaining 1 1/4 cups flour and mix until well combined. Stir in chocolate chips.
Using a large ice-cream scoop, place full scoops of the batter on a cookie sheet with no sides. Bake for 5 minutes or until they start to melt. Remove from oven and place on a cookie sheet with sides or a medium size jelly roll pan. Finish baking about 6 to 10 minutes or until cookie base is dark brown. Remove from oven and let cool. They can be sliced into squares or broken into pieces.
Yield: about 25 cookies