8 ounces semisweet chocolate, roughly chopped
4 tablespoons unsalted butter
2/3 cup all-purpose flour
1/2 teaspoon baking powder
1/2 teaspoon salt
2 large eggs
3/4 cup packed light-brown sugar
1 teaspoon pure vanilla extract
1 package (10-12 ounces) semisweet chocolate chunks/chips

Filling:
5 tablespoons all-purpose flour
1 cup milk
2 teaspoons clear vanilla extract
1 cup butter
1 cup granulated sugar

Ganache:
1 cup whipping cream
8 ounces semisweet chocolate chips