Combine the flour, sugar, butter, eggs, cocoa powder, walnuts, and vanilla essence.
Over low heat, slowly melt the chocolate and butter until they are smooth and blended.
Mix the flour, cocoa powder, and a small amount of salt in a bowl.
For a moist brownie texture, whisk together eggs and sugar until light and fluffy.
To maintain airiness, carefully incorporate the dry mixture into the wet components a little at a time.
To give each mouthful of brownie a crispy texture, fold in chopped walnuts.
Transfer the mixture to a baking dish and bake it at 350°F until the edges become crisp.