Mix egg yolks and sugar until creamy. Warm the milk, add to the egg-sugar mixture and stir well. Heat the mixture again until the yolk binds, do not allow it to boil. Chill well, preferably overnight in the refrigerator.
Chop the walnuts, roast them lightly in the pan and let them cool. Add the whipped cream, walnuts and maple syrup to the chilled mass and place in the ice cream maker. The mixing time depends on the machine.