Grind the cookies and mix 120g (¼ lbs.) with 60g (2.1 oz.) melted butter. Then spread out the mix in a mold and set aside.
Beat the egg whites until stiff peaks form. Gradually add 170g (6 oz.) sugar, then the hazelnut flour, flour and cocoa. Spread out the meringue over the cookie mix. Bake for 20 minutes at 180°C (350°F).
To prepare the coating, whisk the egg yolks, leftover sugar, leftover butter, melted chocolate and ½ orange juice into a light cream. Add the zest of the orange. Coat the meringue with this mix. Bake for 20 minutes at 170°C (340°F). Sprinkle with cocoa and cut the pavé in regular slices.