Pre-heat oven to 350 degrees.  Take melted butter and flour and prepare the cake tins

Whisk the flour, baking powder, baking soda, salt, and 1 1/2 cups sugar

Meanwhile in a separate bowl, whisk together the melted butter, oil, buttermilk, vanilla extract, and egg yolks

In the kitchen mixer, beat the egg whites at medium speed until it starts to peak.  Add the remaining 1/4 cup sugar and continue to beat until stiff peaks form.  Transfer to another bowl and set aside

Add the flour mixture to the empty kitchen mixer bowl (you will need to dry it out from the egg mixture).  Gradually pour the butter mixture to the flour mixture and mix until incorporated.  Stop and scrape the sides of the bowl to make sure you get everything incorporated  

Remove the batter and stir in 1/3 of the egg whites.  Then add the remaining whites and fold the batter

Fill into the pans about 3/4 full.  Bake for 8-12 minutes.  Let cool and frost.

Using a hand mixer, beat the butter until smooth.  Add the powdered sugar and beat until fluffy

And the vanilla and cream and mix until everything is completely incorporated.

Start frosting the in-between layers of the cake.  Then start from the top with the remaining frosting and ice the rest of the cake