Hi me and my daughter made one the other day not sure if its the same one but we did it like this-
Toffee mullers x2 natural fromage frais canderel to taste and one small funsize pack of maltesers 4.5syns mix it all up then freeze it stirring every 30 mins then after about 3 hours it was perfect, if u leave it too long its just a block of ice with no flavour, hope this helps xx