In a mixing bowl, combine the cake mix, eggs, brown sugar, melted butter, and water.
Stir in 1 1/2 cups chocolate chips.
Spread into a greased 9x13-inch pan.
Bake for 18 to 22 minutes, or until light brown.
In a small bowl, melt shortening (or coconut oil) and the remaining 1/2 cup of chocolate chips in the microwave; drizzle over the top (or just spread it if you don't feel like drizzling).
Cut into bars and enjoy!
Notes
I don't have luck with store-brand or cheap cake mixes. I used a Betty Crocker one, and it had great results.
Depending on your preferences, you can use milk, semi-sweet, dark chocolate chips, or a combination.
Wait until the cookie bars have cooled for at least 20 minutes and the chocolate drizzle has settled before cutting into them.
These bars can be kept in the fridge for up to a week and in the freezer for a couple of months.