1. Preheat the oven to 350 F and line an 8 x 8″ baking pan with parchment paper. In a large mixing bowl, whisk together 2 eggs for about 15 seconds, until frothy. Add the Nutella, flour and salt and stir everything together with a large mixing spoon.
2. Empty the batter into the prepared pan, and bake for 18-20 minutes, or until a toothpick inserted in the middle comes out clean. The sides of the brownies should begin to pull away from the parchment, and the middle should not be too wiggly. Remove the brownies and allow them to cool for a 10 minutes before frosting (optional).
3. Prepare the Nutella frosting. In a microwave-safe bowl, heat the chocolate chips for 30 seconds. Remove and add the Nutella, stirring everything together. Microwave again for 15 seconds, then stir until smooth. Use a spatula to spread the warm frosting over the warm brownies. Allow everything to cool and set for 20 minutes before slicing into 16 bars and serving.

Leftover brownies can be kept at room temperature for 3-4 days in an airtight container. Unfrosted brownies may be frozen for up to 2 months. Thaw overnight in the fridge before frosting.