In the 1950s, Gourmet was quite smitten with wafer cookies, and these are the ideal chocolate version—thin and deeply chocolaty. To make for easy rolling, chill the dough until quite firm (overnight is best). “Although we’ve retested the recipes,” say the editors, “ in the interest of authenticity we’ve left them unchanged: The instructions below are still exactly as they were originally printed.” I took the liberty of updating the format by listing the ingredients first and numbering the steps below. I would also recommend chilling the dough thoroughly before rolling out; or chill it in logs and slice the logs paper thin to get the rounds.
(Makes six dozen cookies)
3/4 cup butter
1 1/4 cups sugar
1 tablespoon rum extract
1 egg
1 1/2 cups sifted flour
3/4 cup (unsweetened) breakfast cocoa
1 1/2 teaspoons double-action baking powder
1/4 teaspoon salt

1.) Cream 3/4 cup butter, add gradually 1 1/4 cups sugar, and cream them together until light and fluffy. Add 1 tablespoon rum extract and 1 egg to the butter-sugar mixture and beat thoroughly.
2.) Sift together 1 1/2 cups sifted flour, 3/4 cup breakfast cocoa, 1 1/2 teaspoons double-action baking powder, and 1/4 teaspoon salt. Add the sifted dry ingredients gradually, mixing well after each addition to make a light dough.
3.) Roll the dough out 1/8 inch in thickness on a lightly floured board and cut it with a floured cooky cutter into rounds about 2 1/2 inches in diameter.
4.) Place the rounds on an ungreased baking sheet in a hot oven (400° F.) and bake for 8 minutes. Six dozen cookies are yours.