Pre-heat oven to 350 degrees and grease/spray an 8x8 square pan with non-stick spray and line with parchment paper.

In a small bowl, whisk together cornstarch, cocoa powder, and salt then set aside.

Add the chocolate chips and butter to a medium sized microwave safe bowl. Heat for 20 seconds and then stir. Continue to heat in 10 second intervals until the chocolate is melted. Stir in the chocolate hazelnut spread and add vanilla extract and sugar; stir to combine. Mix in the eggs one at a time until completely incorporated.

Add the dry ingredients into the wet ingredients mixing well. Pour batter into the prepared baking pan and bake for 35 min. (or longer). Cool completely before cutting.