Duke's 100th Anniversary Cake – Duke's Mayo

Ingredients

• 21/3 cups all-purpose flour
• 1 Tbsp. baking powder
• 3/4 tsp. salt
• 11/2 cups sugar
• 1 cup Duke's Mayonnaise
• 2 eggs
• 11/2 tsp. pure vanilla extract
• 3/4 cup milk
• 1/2 cup butter, softened
• 1/2 cup shortening
• 1 tsp. pure vanilla extract
• 5 cups powdered sugar
• 6-8 Tbsp. milk or cream
• 1/2 cup rainbow sprinkles