Put the butter, sugar and salt in a bowl and knead with the dough hooks.
Add the flour and knead everything to a dough. Wrap the dough in foil and refrigerate for about 30 minutes.
Roll out the dough on a floured work surface and cut out footballs with a cookie cutter (about 3x4 cm). [amazon link = "B00KJ8IRE4" title = "This cookie cutter is a bit bigger" /]
Place the footballs on a baking tray with baking paper and bake in preheated oven at 175°C top/bottom heat for 10-12 minutes.
Remove and allow to cool.
Sift the icing sugar, and put about half in a bowl. Put the egg whites and lemon juice in the bowl and mix everything with a mixer.
Gradually add the remaining icing sugar. The mass must be so strong that you can make a fine line without it runs.
Fill approx. 1/2 tbsp icing into a small piping bag and set aside. Dye the rest in brown and fill in about 2 tbsp. also in a small piping bag.
Dilute the remaining icing with water. It should so liquit that it runs flat when you put it on a cookie. Cover the icinig with a damp cloth and set aside.
Make a outside line on the cookie with the brown icing in the piping bag, so that the liquit icing does not run down. Then fill the cookie with the brown liquit icing and leave to dry for about 1-2 hours.
Make the decoration with the icings and allow to dry.