For 4-6 servings:
Shell the walnuts and remove the film which covers them by plunging them into boiling water. Pound them in a mortar with the garlic clove and then add the breadcrumbs which have been moistened in some water (or milk) and squeezed dry, and a handful of salt. Use the pestle like a spoon to mix the ingredients together to obtain a smooth cream. In a saucepan, warm the nut mixture over a moderate heat, diluting with the cream and a few spoonfuls of oil. Turn off the heat before the sauce boils.
Drain the spaghetti when al dente and flavour with the nut sauce. Sprinklewith a little grated nutmeg.