Sift flour and baking soda together, set aside.

In a large bowl, whisk butter or margarine, groundnut paste and sugar together. Add in egg and vanilla essence and mix together. Add in sifted flour and baking soda. Fold in roasted groundnuts. Cover tightly with a rubber and chill for an hour or up to three days.

Pre-heat an oven to 180˚C or 350˚F and grease two baking sheets or line to baking sheets with baking paper. Roll tablespoon of dough onto baking sheet. Bake for 9-10 minutes.

Remove pan from the oven and gently press biscuits with the bottom of a glass. Put baking pan back into the oven and bake for additional 3 minutes and remove from oven. Biscuits will be very soft. Leave on the baking sheet to cook continuously for 10-15 minutes before transferring to a wire rack to cool completely.

Biscuits can be stored at room temperature for 7 days. Biscuit dough can be kept in the freezer for 3 months.