Pre-heat oven to 160 degrees C. Prepare a 23x23cm baking pan by lining bottom with either greaseproof paper or baking paper. Grease the paper.
Separate the eggs and reserve the whites. Beat egg yolks until thick and tripled in volume. Add sugar slowly, beating until very thick. Slowly fold in nuts and essence. Beat egg whites until stiff but not dry. Fold them into the yolk mixture. Pour batter into prepared pan.
Bake for one hour or until done. Cool in pan for 10 minutes then turn out and remove paper. Cool completely. Cut as needed.