Preheat your oven to 350°F and grease a 9x13 inch baking pan with cooking spray.

In a large bowl, cream together the butter and sugar until light and fluffy.

Add the eggs, one at a time, and beat well after each addition.

Add the milk, heavy cream, and vanilla extract to the bowl and mix well.

In a separate bowl, whisk together the flour, baking powder, and salt.

Gradually add the dry ingredients to the wet mixture, beating until just combined.

Pour the batter into the prepared pan and bake for 25-30 minutes or until a toothpick inserted in the center comes out clean.

While the cake is baking, prepare the topping. In a medium saucepan, combine the heavy cream, sugar, and butter over medium heat. Stir until the sugar has dissolved and the mixture is smooth.

Add the milk powder and stir until the mixture is thick and creamy.

Pour the topping over the cake and spread it out evenly with a spatula.

Allow the cake to cool completely before serving. Enjoy!