Heat oven to 160C/140C fan/gas 3 and
line a 12-hole muffin tin with cases. Put
85g pistachios into a food processor with
about half the sugar, then whizz until very
finely chopped. Tip into a large mixing
bowl with the remaining sugar, butter,
eggs, flour and milk and beat until smooth.
Divide between cases, then bake on a low
shelf for 22-25 mins until a skewer poked
in comes out clean. Cool on a wire rack.
For the icing, mix just enough water
into the icing sugar to get a very thick but
still runny icing – just add 1 tbsp of water
at a time. Stir in enough food colouring
to give a pretty, pale green colour. If any
cakes poke above the top of the cases,
trim with a small knife, or scoop out with
a teaspoon – being very careful not to
release any of the case from the sides of
the cake. Put a generous spoonful of icing
on each cake and let it gently spread to
cover. Chop the remaining pistachios and
scatter these over with a pinch of edible
glitter. Set, then serve.