1 1/4 cups all-purpose flour
2 teaspoons baking soda
2 teaspoons baking powder
1/4 teaspoon salt
1 1/4 cups granulated sugar
4 ounces unsweetened chocolate, chopped
1 stick unsalted butter, cut into pieces
2 teaspoons vanilla extract
2 large eggs, lightly beaten
4 tablespoons unsalted butter, at room temperature
1 cup confectioners' sugar
2 teaspoons vanilla extract
3 tablespoons heavy cream
1 cup marshmallow creme
6 ounces bittersweet chocolate, chopped
1/2 cup heavy cream
1 stick plus 1 tablespoon unsalted butter
2 1/4 teaspoons vanilla extract
1 tablespoon milk
2 cups confectioners' sugar