White Velvet Cake with Cheesecake Filling and Silky Marshmallow Buttercream

By RoketJSquerl

Ingredients

• 12 tablespoons (6 ounces, or 170 grams) unsalted butter, softened
• 1/2 cup (4 ounces, 113 grams) vegetable oil
• 14 ounces (397 grams) granulated sugar-2 cups
• 3 large eggs
• 1 cup (237 milliliters) buttermilk
• 1/2 cup (119 milliliters) sour cream
• 1 tablespoon (15 milliliters) vinegar
• 1 tablespoon (15 milliliters) vanilla
• 6 ounces (170 grams) all-purpose flour-1 1/4 cups
• 5 1/2 ounces (156 grams) cake flour- 1 1/4 cups* (see end of recipe for substitute)
• 1 1/2 teaspoons (7 1/2 milliliters) baking soda
• 3/4 teaspoon (3 3/4 milliliters) salt
• 5 ounces (142 grams) granulated sugar-3/4 cup
• 2 tablespoons (30 milliliters) all-purpose flour
• Pinch of salt
• 3 large eggs
• 2 (8 ounce, or 227 gram) packages cream cheese, softened
• 1/2 tablespoon (7 1/2 milliliters) vanilla extract
• 2 tablespoons (30 milliliters) sour cream
• 7 ounces (198 grams) large marshmallows
• 5 ounces (142 grams) corn syrup
• 3 ounces (85 grams) granulated sugar
• 1 teaspoon (5 milliliters) water
• 2 cups (16 ounces or 454 grams) unsalted butter, softened
• 1/4 cup (60 milliliters) cold pasteurized egg whites
• 1 cup confectioner’s sugar (4 ounces or 114 grams) or to taste up to 3 cups
• 1 tablespoons (15 milliliters) vanilla extract
• 1/2 tablespoon (7 1/2 milliliters) vanilla bean paste or more vanilla extract

Details

Servings 1
Adapted from cakepaperparty.com

Preparation

Step 1

Preheat oven to 350 F (177 C). Spray three 8-inch round cake pans with Baker’s Joy or grease and flour.

Beat butter, oil and sugar on medium-high speed for 2 minutes. Add eggs one at a time and beat until incorporated. Add buttermilk, sour cream, vinegar and vanilla and mix to blend.

Sprinkle in flours, baking soda and salt; beat for 1 minute.

Pour into prepared pans and bake for about 25-30 minutes until a cake tester comes out clean. Cool 10 minutes in pan and then turn out to a cooling rack. Cool completely if using immediately, or wrap in two layers of plastic wrap if using later. Frost the cooled cake with your buttercream of choice.

*Cake flour substitute: Use 137 grams all-purpose plain flour and 19 grams cornstarch or potato starch in place of cake flour.

In a small bowl combine sugar, flour and salt and stir to blend. Whisk in eggs.

Place softened cream cheese in a medium bowl and whisk in 1/3 of the egg mixture. Add remaining egg mixture in two batches whisking after each addition. Whisk in vanilla and sour cream.

Pour the cheesecake mixture into the top of a double boiler and place over simmering water. Whisk constantly over medium-low heat until the mixture is very thick. About 10 minutes. Scrape the corners and edges frequently. When it is the consistency of peanut butter remove from the heat.

Pour the cheesecake mixture into an 8-inch cake pan and cover the surface directly with plastic wrap or wax paper. Place in the freezer to cool for 30 minutes or until chilled.

Place marshmallows, corn syrup, sugar and water in a microwave safe bowl and heat on high for about 1 ½ to 2 minutes until the marshmallows are melted and the sugar is dissolved; stir after one minute and then at 20 second intervals. Scrape into a mixer bowl and place in freezer for about 20 minutes or until cool to the touch.

When cool, add the butter to the mixer bowl and beat on medium-high for 2 minutes. Reduce the speed to medium-low and pour in the cold egg whites; beat on medium-high for 1 minute.

Add the confectioner’s sugar and vanilla to the marshmallow-butter mix and beat to combine.

Makes about 5 ½ cups