Sunshine Cake | Saveur

Ingredients

• 18 large eggs, separated
• 2 cups sugar
• 2 tsp. cream of tartar
• 1⁄2 tsp. salt
• 2 tsp. pure vanilla extract
• 8 large egg yolks, plus 1 1/2 cups egg whites
• 1 1⁄2 cups powdered sugar
• 1 1⁄2 cups milk
• 2 cups softened unsalted butter
• 3 tsp. pure vanilla extract
• 3 cups granular sugar
• 1 1⁄2 cups water
• 3 tsp. cream of tartar
• 1 pinch salt