Finely chop the walnuts. Sift icing sugar. Beat egg white and salt until stiff. While continuing to beat, gradually add the icing sugar. Mix all nuts and fold in.
Pour into a piping bag with a large perforated spout. Spray approx. 40 tuffs (3 cm Ø) onto trays lined with baking paper. Let dry for 3 hours at room temperature. Bake in a hot oven (electric cooker: 175 °C/ convection oven: 150 °C/gas: level 2) for approx. 18 minutes. Cooling down
Chop the couverture and melt in a hot water bath. Kusserln with couverture sometimes whole and sometimes in strips. Decorate with nuts etc. Let the chocolate coating dry