Pre heat oven to 180 C
In a bowl, beat butter with the sugar until light and fluffy.
Add the egg and vanilla extract and mix.
Sift the flour with the salt and add to the mixture.
Transfer the dough to a working surface and knead with hand to form the dough.
Cover with plastic wrap and refrigerate for one hour.
Remove from the fridge and now take a small portion of the dough and mix it with cocoa powder to make it brown for the cow patches.
Roll the white dough and put patches of brown dough in spaces. Use any cookie cutter of your choice and cut shapes.
Transfer into a baking tray and bake in 180 C oven for 10-12 minutes.
