For the cake:4 ounces bittersweet chocolate1 teaspoon vegetable oil2 ¼ cups flour½ cup cocoa powder1 ½ teaspoons baking soda½ teaspoon salt¾ cup (1 ½ sticks) unsalted butter, softened1 ½ cups sugar4 eggs2 teaspoons vanilla extract2 teaspoons white vinegar1 ½ cups milk For the frosting:12 ounces white chocolate chips8 ounces sour cream½ cup (1 stick) unsalted… Continue reading Double-Chocolate Cake