Preheat your oven to 350°F (175°C).
Grease and flour three 8-inch round cake pans.
In a large bowl, cream together the butter and sugar until light and fluffy.
Add the eggs one at a time, beating well after each addition.
Mix in the vanilla extract.
In a separate bowl, combine the flour and baking powder.
Gradually add the dry ingredients to the wet mixture, alternating with milk.
Divide the batter evenly among the prepared pans.
Bake for 25-30 minutes or until a toothpick comes out clean.
Let the cakes cool in the pans for 10 minutes, then transfer to wire racks to cool completely.
Once cooled, layer the cakes with whipped cream between each layer and cover with marzipan.