Easy Ghost Cake - Chefwiz

Ingredients

• Nonstick cooking spray
• 3 1/2 cups all-purpose flour
• 2 tablespoons cornstarch
• 2 teaspoons baking powder
• 1 teaspoon kosher salt
• 1 teaspoon baking soda
• 2 sticks (1 cup) unsalted butter (, room temperature)
• 2 cups granulated sugar
• 3 tablespoons vegetable oil
• 1 tablespoon pure vanilla extract
• 3 large eggs (, room temperature)
• 2 large egg yolks (, room temperature)
• 2 cups buttermilk (, well-shaken)
• 4 sticks (2 cups) unsalted butter (, room temperature)
• 3 tablespoons whole milk
• 2 teaspoons pure vanilla extract
• 1/4 teaspoon kosher salt
• 6 cups confectioners sugar (about 1 1/2 pounds)
• Black gel food coloring