White Wedding Cake

Bahan-bahan (14 porsi)

• One 15.25-ounce box white cake mix ((NOTE: make sure the cake mix you buy is 15.25 ounces-- companies have been reducing the size))
• 1 cup all purpose flour
• 1 cup granulated white sugar
• ¾ teaspoon salt
• 1⅓ cups water
• 2 tablespoons vegetable or canola oil
• 1 teaspoon vanilla extract
• 1 cup sour cream
• 4 large egg whites
• 4½ cups powdered sugar
• 1½ cups (3 sticks) salted butter, (at room temperature)
• 1½ teaspoons vanilla extract ((use clear extract, if you really want it white))
• 3 to 4 tablespoons heavy whipping cream