The Boston cooking-school cook book

by Fannie Merritt Farmer

Chocolate Filling

2½ squares chocolate

1 cup powdered sugar

3 tablespoons milk

Yolk 1 egg

½ teaspoon vanilla

Melt chocolate over hot water, add one-half the sugar, and milk; add remaining sugar, and yolk of egg; then cook in double boiler until it thickens, stirring constantly at first, that mixture may be perfectly smooth. Cool slightly, flavor, and spread.