Banana Pudding Cupcakes

Name: Banana Pudding Cupcakes
Ingredients: 1 cup all-purpose flour; 2/3 cup finely ground vanilla wafer cookies (from about 3/4 cup whole cookies); 1 1/4 teaspoons baking powder; 1/2 teaspoon salt; 1 1/2 sticks (12 tablespoons) unsalted butter, at room temperature; 1/2 cup granulated sugar; 2 large eggs, at room temperature; 1/2 cup milk, at room temperature; 2 teaspoons pure vanilla extract; 1 large banana, peeled and finely chopped; 1/2 cup white chocolate chips; 1/4 cup heavy cream; 2 sticks unsalted butter, at room temperature; Pinch of salt; 2 cups confectioners' sugar; 1 teaspoon pure vanilla extract; 1 to 2 tablespoons milk; Vanilla wafer cookies and banana slices, for topping