Preheat the oven to 350 degrees
In a medium bowl, combine the flour, baking powder, and salt set the bowl aside.
In a large mixing bowl, or using a stand mixer, beat together the butter and sugar, until well combined.
Add in the eggs and vanilla, mixing at medium to high speed for an additional minute.
Gradually add in the flour mixture, scraping the sides of the bowl with a rubber spatula, as necessary.
Pour the cake batter into a lightly sprayed 9x13 baking pan and bake for about 23-25 minutes, until the cake springs to the touch.
Use a fork to poke holes throughout the top of the cake and set the cake aside to cool.
Prepare the filling while the cake is cooling.
To prepare the filling, combine the milk, heavy cream, sweetened condensed milk, and evaporated milk. Whisk together until they are combined, and then pour over the cake, making sure to fill in the holes made with a fork.
Cover and chill the cake for 6-8 hours, or overnight.
To top the cake, whisk the heavy cream until it begins to thicken, and hold its form, like shaving cream. Add in the sugar and vanilla until it is thick whipping cream.
Cover the top of the cake with the whipped cream topping.
Serve cake chilled.