Boil water in the kettle. Coffee into a filter form. Place on a pot. Pour bubbling boiling water over it. Allow coffee to cool.
Mix egg yolks in a saucepan. Place in water bath. Whip until frothy, adding sugar and a pinch of salt. Add coffee and whip until creamy.
Remove saucepan from water bath. Cool while whipping throughout. Fill into 4 glasses. Place in refrigerator to set completely in 10 minutes. In the meantime, whip whipped cream with vanilla sugar until stiff and fill into a piping bag. Garnish the cream with it. Sprinkle with brittle and serve on the spot.