Preheat the oven to 350F and line an 8-inch square pan with parchment.

Whisk the chocolate-hazelnut spread and eggs together until smooth and glossy.

Fold in the flour just until no streaks remain.

Spread the batter evenly into the pan.

Bake for 18 to 20 minutes, until the top is set and a toothpick comes out with moist crumbs.

Cool completely before slicing into squares for clean edges.