Banana Cream Pie Filling
Whisk the milk, vanilla extract, and pudding mix together until combined and slightly thickened, about 2-3 minutes. Fold in the whipped topping, then mix in the chopped bananas. Cover with saran wrap and place in the fridge to chill while you prepare the cookies.
Make the Cookie Base
Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper, setting it aside. In a large mixing bowl or stand mixer, cream together the butter, oil, Imperial Sugar granulated sugar, and Imperial Sugar powdered sugar until light and fluffy. Add the egg and butter vanilla emulsion, mixing until fully incorporated.
Add the flour, salt, and baking powder, mixing until just combined. Using a large cookie scoop, divide the dough into 9 equally-sized balls. Place them on the prepared baking sheet, gently flattening each to about 1 inch in thickness. Use a ¼ measuring cup to press down the center of each cookie, creating a well for the filling.
Bake for 10 minutes, then allow the cookies to cool completely on the baking sheet.
Once the cookies are cooled, top each with a generous spoonful of the banana cream pie filling. Sprinkle with Nilla wafer crumbs and place a mini Nilla wafer in the center for garnish. Enjoy!