Preheat oven to 350°F.
Grease 2 9-inch cake pans, set side.
In a small microwave-safe bowl, melt the chocolate, and the tablespoon of butter in the microwave on medium (50%) heat.
In a large mixing bowl, stir together the stick of butter, the sugar, and the vanilla.
Stir in the eggs, 1 at a time until they are all incorporated.
Stir in the chocolate.
Stir in the salt and oil.
Stir in 1 1/4 cups of the flour then the 1/2 cup of milk.
Stir in the last 1 1/4 cup on flour and the baking powder.
Pour the batter evenly between the 2 cake pans and bake for 20 minutes or until a toothpick comes out clean.