Preheat the oven to 350F or 180C and line a 9x9 inch Baking tray with Parchment Paper
Melt the butter cubes with dark chocolate brick and Chocolate Chips in a skillet over low heat. Keep stirring at 30 seconds interval until you have smooth melted chocolate. Once melted take the Chocolate off the heat and cool it down and stir in about 1/2 cup of Nutella. Save about 2 Tablespoon of Nutella for the swirl on top.
Beat the Eggs and Sugar at medium speed for 3-4 minutes. Add in the Vanilla Extract and mix well.Add the chocolate mixture into this and mix well using a wooden or rubber spatula.
Add the flour and cocoa powder into this wet mixture and mix well with a rubber or wooden spatula.Pour this brownie batter in your lined baking tray. Top with 2 generous dollops of Nutella and swirl it with the back of a spoon or a toothpick over your brownie batter.
Bake your brownies for 35-40 minutes. Insert a toothpick in the center to check. It should come out crumbly. If it comes out moist, your brownies are underbaked. Also, if your toothpick comes out clean, chances are your brownie is overbaked. Cool it quickly and cut it into pieces.