Preheat oven to 350°F. Grease an 8x8 or 9x9 baking pan. Removes the easiest by lining with parchment paper and sprayed with non-stick spray. Set aside.
In a large bowl melt ⅔ cup of chocolate chips at 30 second intervals until smooth (about 1.5 minutes). Add oil and mix.
Slowly add sugar, stirring constantly.
Add eggs, one at a time, mixing well after each addition.
Add vanilla extract and stir.
Add flour, cocoa powder and salt, stirring until combined. Add ⅓ cup of chocolate chips and stir until evenly distributed.
Top with the remaining ⅓ cup of chocolate chips and bake on center rack for 35-40 minutes, or until the edges are set and center is no longer jiggly.
Cool in pan on cooling rack until cooled. Slice and serve!