Melt butter and stir in flour, mixing well. Beat egg yolks with syrup and water. Add to butter-flour mixture and cook over boiling water until thick and creamy, stirring most of the time. Add walnuts and let cool. Pour into an 8-inch pie shell or divide into 6 individual tart molds lined with pastry.

As a variation, sprinkle the nuts on top instead of mixing them in the filling.

To make chiffon maple tarts, beat 2 egg whites until stiff, fold into cooked and cooled maple cream, then pour into baked tart shells.