Preheat the oven to 350 degrees Fahrenheit.
Add 1 1/3 cup of chocolate chips to a bowl with the butter and melt in the microwave using 30 second intervals. Stir well between each interval. Alternatively, add to a double boiler and melt on the stove.
Meanwhile, beat together the eggs, sugar and vanilla with an electrix mixer.
Beat in the melted chocolate/butter.
Fold in the flour, cocoa and salt until well combined. Fold in the remaining 1/3 cup of chocolate chips.
Add half of the batter to a lined 8x8 baking pan and spread evenly. Add 16 oreos (4 rows of 4), then spread on top the rest of the batter. Add 4 more crushed oreos on top.
Bake for 28-34 minutes or until a toothpick comes out mostly clean. If you like fudgier brownies, bake for less time, if you like them more well done, bake for longer.
Let cool, then slice around the edges of the pan and lift out by the parchment paper. Slice into 16 squares (so there will be one oreo inside each brownie) and enjoy!