Black-and-White Chocolate Marble Pound Cake with Vanilla Bean and Black Cocoa Glazes

INGREDIENTS

2 cups

unsalted butter, room temperature and divided

3 cups

granulated sugar, divided

3 tsp

vanilla extract,divided

large egg whites (120 grams),room temperature

4 oz

white chocolate, melted

2 1/4 cups

cake flour, divided

2 tsp

kosher salt, divided

large eggs (100 grams), room temperature

large egg yolks (74 grams), room temperature

3/4 cup

black (Dutch process) cocoa powder*, sifted

1/2 cup

whole buttermilk, room temperature

Vanilla Bean Glaze (recipe follows)

Black Cocoa Glaze (recipe follows)