Banana Bread Lava Cake

Name: Banana Bread Lava Cake
Ingredients: 1 stick (8 tablespoons) unsalted butter, melted, plus more for greasing; 1 1/4 cups all-purpose flour, plus more for dusting the pan; 1/2 teaspoon baking powder; 1/2 teaspoon baking soda; 1/2 teaspoon kosher salt; 1/2 teaspoon ground cinnamon; 1/4 teaspoon ground allspice; 1/4 teaspoon ground ginger; 1/2 cup granulated sugar; 1/2 cup light brown sugar; 1/2 cup mashed banana (from about 2 bananas); 1/4 cup sour cream; 2 large eggs; 1 teaspoon pure vanilla extract; 2 chocolate-coated vanilla ice cream bars, such as Klondike; Confectioners' sugar, for dusting