Put the milk, cream and marshmallows in a large enough saucepan and heat until it is almost boiling. Remove from heat and stir until the marshmallows are melted.
Beat the egg yolks and sugar. Pour the hot marshmallow milk over it; then put everything back into the pot. Heat over a moderate heat while stirring until the mass gets some consistency. Then let cool down completely.
Then place in the ice cream maker or in the freezer and stir vigorously every hour.
When the ice cream is almost completely firm, stir in the coarsely chopped macadamias.