White Chocolate Fudge Cake

1 package white cake mix, 18.25 oz.
1 1/4 cups water
3 egg whites
1/3 cup oil
2 teaspoons vanilla extract, divided
6 ounces white baking chocolate, melted, divided
1 cup semisweet chocolate chips
1/4 cup powdered sugar
2 tablespoons 2% milk3 tablespoons butter, no substitutes
2 tablespoons light corn syrup
16 ounces vanilla frosting
8 ounces Cool Whip®


Combine cake mix, water, egg whites oil and 1 teaspoon vanilla. Beat on low for 2 minutes. Stir in 1/2 white chocolate. Pour into a greased 9x13 pan. Bake at 350 degrees for 25-30 minutes or until toothpick comes out clean. Cool for 5 minutes. In a small pan over low heat melt chocolate chips, milk, powdered sugar, butter and corn syrup, pour over cake, cool completely. In a bowl beat frosting, stir in rest of the white chocolate, vanilla, fold in cool whip. Frost cake store in refrigerator.