This recipe is from a 1956 Borden's Eagle Brand booklet. It has 70 "Magic Recipes", the puddings, custards, pies, and candies, but it also has quite a few cookie recipes. I love this retro photo, the cherries with stems are great.
Magic Chocolate Pie
1 baked 8-inch pastry pie shell, cooled
1 1/3 cups (15 oz. can) Eagle Brand
2 squares (2 oz.) unsweetened chocolate
1/3 teaspoons salt
1/2 cup hot water
1/2 teaspoon vanilla extract
1/2 cup Borden's Heavy Cream, whipped
In top of double boiler put Eagle Brand Sweetened Condensed Milk, chocolate and salt. Heat over rapidly boiling water, stirring constantly, until mixture is very thick. Gradually stir in water, keeping mixture smooth. Continue cooking, stirring often, until mixture thickens. Remove from heat. Stir in vanilla extract. Pour into pie shell. Cool at room temperature about 1/2 hour. Refrigerate at least 3 hours. Just before serving garnish with whipped cream.