Crush Marie biscuits into crumbs

Beat the egg tether with the vanilla essence.

Melt the margarine in a large saucepan over a low heat on the stove.

Add the icing sugar, cocoa and the egg and vanilla essence mixture and stir until smooth.
Remove from the stove.
Add the crushed Marie biscuits and mix well.

Pour the hot fudge onto a well greased baking pan. Spread mixture until you have an even layer.

Allow to cool and cut into squares.