Beat egg whites with salt until stiff. Fold in all other ingredients. Pour into a loaf pan that is coated or lined with baking paper. Bake at 200 ° until the surface is light brown.
Let cool down. Use the electric knife (if available) to cut into 1 cm thick slices. Place on a baking sheet and bake dry on a low heat (100 - 120 °, preferably fan-assisted).