Begin the cake recipe by preheating the oven to 350 degrees F. and lightly spraying an 8x8-inch square baking pan with non-stick cooking spray. Set aside. In a small bowl, whisk together the 1 ½ cups all-purpose flour, 2 teaspoons baking powder, and ⅛ teaspoon kosher salt. Set this bowl aside.
In a separate medium bowl, using a mixer, mix together the ½ cup granulated sugar, ¾ cup milk, 1 large egg, 4 tablespoons melted butter, and 1 teaspoon vanilla extract until smooth and combined.
Pour the cake mixture into the prepared square baking pan. Then set aside while you mix the cinnamon roll topping.
In a small bowl, using a whisk, combine the ½ cup softened butter, 1 tablespoon all-purpose flour, and ½ tablesponn ground cinnamon until it is smooth. Pour evenly on top of the cake mixture in the baking pan. Place into the oven and bake 30 to 40 minutes or until a cake tester comes out clean.
Once you carefully remove the finished cake from the oven allow it to cool while preparing the glaze topping.
In a small bowl, stir together the 1 cup powdered sugar, 2 tablespoons milk, and ½ teaspoon vanilla extract until combined. Pour evenly over the cake while it is still warm and spread evenly over the top. Allow the cake to continue to cool in the baking pan on a wire rack before cutting to serve. Enjoy!