Preheat Oven: Preheat your oven to 325°F (163°C).
Mix Ingredients: In a medium bowl, combine the slightly beaten eggs, granulated sugar, and salt. Gradually add the scalded milk, stirring continuously. Add vanilla extract and mix well. Stir in the Grape-Nuts cereal.
Prepare Baking Dish: Pour the custard mixture into an 8x8-inch baking dish. Place the dish in a large roasting pan and fill the pan with hot water, reaching halfway up the sides of the custard dish.
Bake: Bake for 40-50 minutes, or until a knife inserted into the center comes out clean.
Cool and Serve: Allow to cool slightly before serving. Enjoy warm or chilled, with a topping of cream or Cool Whip if desired.