I loved my grandaddy Paulk, my mom’s dad. He always made us feel like we were the most special children in the world. When he and Grandma would come to visit, he had a smile for everybody and a laugh that was contagious. He loved a good meal. Grandma was such a wonderful cook, and she always had an amazing meal waiting for him when he would come in from working in the field or at the dairy barn. When he came to our house for his birthday, my mom would make this cake for him.
In a small saucepan, combine the water, ½ cup of the sugar, and the chocolate. Heat over low heat, stirring constantly, until thick (see Note). Remove the pan from the heat and add the vanilla. Set aside to cool.
Preheat the oven to 350°F. Prepare three 9-inch round cake pans by greasing and lining each with parchment paper.
Sift the flour with the baking powder and salt onto waxed paper. Cream the butter and the remaining 1¾ cups sugar until smooth. Add the eggs, one at a time, beating after each addition. Add the cooled chocolate mixture and beat until smooth. Add the sifted flour mixture alternately with the milk, starting with a third of the flour, then adding half the milk, and ending with the flour. Stir only enough after each addition to blend the ingredients. Pour evenly into the pans and bake for 35 minutes, or until done. Judge doneness by appearance—layers will begin to pull away from the sides—or by inserting a toothpick in the center of a layer. The toothpick should come out clean. Cool in the pans for 10 minutes, then turn out onto racks. Remove the paper and cool completely before frosting. Spread the icing between the layers and on the top and sides of the cake.
Put the egg whites and salt in the bowl of a mixer that uses 2 beaters. Beat the whites until smooth but not stiff. They should not form stiff peaks when the beaters are lifted up.
In a large saucepan with a cover, mix the sugar, water, corn syrup, and vinegar. Stir until the sugar dissolves, then cover and cook for 3 minutes to melt any sugar crystals that may be on the sides of the saucepan. Remove the lid and continue cooking for about 12 minutes, until the mixture reaches the hard ball stage, about 265°F on a candy thermometer. The syrup will spin a long thread when poured from the edge of a spoon. Remove the syrup from the heat and stir in the marshmallows. The mixture will be foamy. With the mixer running at high speed, stream the syrup into the egg whites, following the groove the beaters make as the bowl turns. Beat well and add the vanilla.
The chocolate may be melted with ½ cup of sugar in 1 cup of water in the microwave. My mother, Lizzie, used one large marshmallow for each egg white for perfect divinity icing.