Pre-heat oven to 170˚C.
Line 2 large baking trays with baking paper.
In a large bowl, cream butter and sugar together until soft and fluffy.
Beat in the egg and mix well.
Add the condensed milk, golden syrup, vanilla and mix thoroughly.
Sift in the flour, baking soda, cream of tartar and add a pinch of salt. Combine well into a dough. Knead lightly if necessary.
Form biscuits with a cookie press or roll into small balls, place on prepared trays and flatten with a fork.
Bake for about 10-15 minutes, until lightly golden.
Once cool, store in an airtight container.