Yes it's green but bare with me . This is another blast from school days
Mix the cornflour, sugar and 1-2tblspns of the milk to make a smooth paste.
Heat the remaining milk gently until almost boiling.
Pour into the cornflour paste, stirring well.
Pour it back into the pan and put it back on the heat, stirring continuously until thickensand boils
Turn down to a simmer for 2-3 minutes
Take off of heat and stir in the colouring and peppermint, mix well.
Serve with chocolate concrete