White Cake with Vanilla Buttercream - Baking with Blondie

Name: White Cake with Vanilla Buttercream - Baking with Blondie
Cuisine: American
Ingredients: White Cake [br]; ⅔ Cup Sour Cream; ¾ Cup Buttermilk (room temp); 1 Tablespoon Mexican Vanilla; 4 Egg Whites (room temp); ⅓ Cup Vegetable Oil; 1 Duncan Hines White Cake Mix; [br]; Vanilla Bean Buttercream [br]; 3 sticks unsalted butter; 1 Tablespoon Vanilla; 1/2 Tablespoon Vanilla Bean Paste; Pinch of Salt; 1/4 Cup Heavy Cream; 6-7 Cups Sifted Powdered Sugar; Sweetapolita “It’s Vintage” Sprinkles