line a lamington tin or even a roasting pan with foil with enough extra to fold back over the top. Dimensions must be in multiples of SAO biscuits; either 3x4 or 4x3.
place SAO Biscuits in a 3x4 or 4x3 pattern on bottom (if need be use rolled paper to make a 'wall' to hold the edge.
Pour thickened cream into bowl and pour pack of vanilla instant pudding mix over the top (can add a few drops of vanilla extract or essence for added flavour). Whisk quickly and make sure all powder is dissolved, it thickens quickly.
pour mix over base of biscuits, spread as evenly as you can.
place an equal number of SAO biscuits over the filling, pressing down to even it out if need be.
make a tangy lemon icing with icing sugar, melted marg (about 1 teaspoonful) and enough lemon juice and maybe a little boiling water - spread over the top of the top layer of SAO biscuits then seal with the extra foil left over.
Leave in fridge overnight.
take all out of foil and cut each SAO in half plus cut between each biscuit square. Makes 24.
Tip: must be left overnight, but 24 hours is better.