Here’s an old recipe clipped from a newspaper that is a promo piece for Jack Frost Confectioners Sugar, date unknown. Recipe is typed below along with a scanned copy.

JIFFY CHOCOLATE FROSTING
(Covers loaf cake*)

3 squares unsweetened chocolate
1 1/2 cups sifted Jack Frost Confectioners XXXX Sugar (about)
2 tablespoons hot water
1 egg
4 tablespoons softened butter
Dash of salt
1 teaspoon vanilla

1. Melt chocolate over hot water.
2. Add sifted Jack Frost Confectioners XXXX Sugar and hot water. Mix thoroughly. It’s the amazing fineness of Jack Frost XXXX Sugar that gives frosting such delightful satiny smoothness.
3. Add egg. Beat well.
4. Add butter, 2 tablespoons at a time, and beat after each addition, until smooth.
5. Add salt and vanilla.
6. Spread on warm cake. Let stand until set.
7. This is a delicious soft frosting. If a firmer frosting is desired, add more sifted Jack Frost Confectioners XXXX Sugar.

(Other fine recipes on the Jack Frost package.)

*Or covers tops of two 8-inch layers.