Whip the butter with a hand mixer/stand mixer till it changes color to pale yellow.
Add sifter sugar,salt,Vanilla extract,milk and cocoa.First incorporate with a spatula so that the dry confectioners sugar and cocoa doesn't fly everywhere.
Whip it together with a hand or stand mixer for about 10-15 minutes while scrapping the sides and bottom with a soft spatula.
Peanut Butter Cake
Heat the butter in a pan.Once it has melted add the peanut butter and oil-Whisk till smooth.Set aside to cool.
Next break the eggs in a large bowl.Add the sugar,Baking soda,Salt,Baking powder and sugar.Whisk together with a electric hand whisker or in a stand machine.This takes 5-8 minutes.
Now trickle in the peanut butter-oil-butter mixture slowly, all the while whisking.Mix till incorporated.
Add half the flour,Mix.Add in the butter milk and mix.Add rest of the flour.
Fold everything together-Scrape the sides and bottom of the bowl.
Bake for 35-40 minutes in a preheated oven at 180 degrees.Test with a toothpick.If it comes out clean remove the cake from the oven.If the toothpick has wet batter stuck to it,Bake for another 10 minutes.
If the cake is browning too much but under cooked inside,Cover with aluminium foil and continue baking.