Preheat the oven to 375°F. Grease a 9 by 13-inch baking dish and set it aside.
Combine the sugar, egg, butter, flour, baking powder, salt, vanilla, and milk in a large mixing bowl. When the mixture has a creamy consistency, spread it into the prepared pan.
To make the topping, mix all the topping ingredients in a small bowl.
Sprinkle over the cake batter.
Bake for 20 minutes, or until a toothpick inserted into the center comes out clean.
Recipe by Amish 365 at https://www.amish365.com/5-favorite-amish-country-bed-breakfasts/