I've had an idea for biscuit flavourings kicking round my head for a wee while and since I had this Saturday morning free, I gave it a go...

I made 3 flavours. 

Rose - 2 tbsp ground up rose petals and  1/4 tsp rose extract (from Lakeland)

Pistachio - ground up handful of pistachio nuts and 1/4 tsp pistachio nut paste (recent purchase from Sous Chef in preparation for making pistachio macarons) & tiny amount green food colouring

Lemon - grated lemon zest and 1/4 tsp lemon extract

 The basic shortbread recipe is:

140gm softened (room temperature) butter

170 gms plain flour

55gms cornflour

55 gms icing sugar

Put it all in a bowl and rub together with your fingers.  While still crumby, divide into 3 bowls and add the rose, pistachio and lemon flavourings to each bowl then rub together to form a pastry.

Roll out each flavoured pastry to about 5mm thick.  Then if you have a range of round cutters cut out both big and small circles from each flavour and fill the centre of a big biscuit with the small circle of a different flavour ie mix them up.  So put a small lemon circle inside a big rose circle or vice versa or pistachio with lemon or rose.  The picture below should explain that a bit more clearly.  See how the biscuit centers are different colours?  That.  But if you're not in the mood for faff, just cut out single round biscuits, they taste just as nice :)

Heat the oven to 170 Celsius fan or 190 non-fan and bake for between 14-16 minutes.  Take them out when they're still quite pale and try not to let the edges turn brown.  Try to let them cool before eating.