Bring milk, powdered milk, sugar and cornstarch to boiling in saucepan over low heat, stirring constantly, until thickened, 15 to 20 minutes; then boil 30 seconds. Remove from heat. Add vanilla. Strain into bowl.
Place plastic wrap directly on surface of custard. Refrigerate until chilled and firm, about 30 minutes.
Puree strawberries and sugar in blender or food processor.
In parfait glasses or custard cups, alternate layers of pudding, coulis and sliced berries. Chill. Makes 8 servings.