Preheat oven to 350.
Line an 8?8 baking pan with parchment paper.
Beat eggs on high 7-10 minutes (until they roughly triple in size).
Heat Nutella by microwaving for 60 seconds, stirring and repeating until very warm.
Slowly add warm Nutella to eggs, beating until thoroughly combined.
Pour batter into prepared pan and bake for 30 to 35 minutes (until a toothpick inserted in center comes out almost clean).
Cool completely before cutting.
Optionally, dust with powdered sugar.