- Bottom Layer:
- 3 cups all-purpose flour
- 1 1/2 cups milk
- 1 cup white sugar
- 2 eggs
- 4 teaspoons baking powder
- 2 teaspoons vanilla extract
- 1/4 teaspoon salt
- 1/4 cup butter, melted
- Top Layer:
- 1 cup butter, softened
- 1 cup brown sugar
- 2 tablespoons all-purpose flour
- 1 tablespoon ground cinnamon
- Glaze:
- 2 cups confectioners' sugar
- 5 tablespoons milk
- 1 teaspoon vanilla extract
- Preheat oven to 350 degrees F (175 degrees C). Grease a 9×13-inch baking pan.
- Mix 3 cups flour, milk, white sugar, eggs, baking powder, 2 teaspoons vanilla extract, and salt together in a large bowl until well-combined. Stir in 1/4 cup melted butter. Pour batter into the prepared baking pan.
- Beat 1 cup softened butter, brown sugar, 2 tablespoons flour, and cinnamon together in a large bowl until smooth. Drop by spoonfuls over the batter in the baking pan. Swirl the top layer into the bottom layer with a knife to create a marble effect.
- Bake in the preheated oven until a toothpick inserted into the center comes out nearly clean, 25 to 30 minutes.
- Mix confectioners' sugar, milk, and 1 teaspoon vanilla extract in a large bowl until smooth. Drizzle over warm cake.