Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a bowl, mix the banana cake mix, vegetable oil, and eggs until a thick dough forms.
Scoop out tablespoon-sized portions of dough, roll into balls, and place them on the baking sheet.
Bake for 10–12 minutes, or until the edges are set and the cookies are lightly golden. Allow to cool completely.
Step 2: Prepare the Filling

In a mixing bowl, whisk together the banana pudding mix and cold milk until it thickens.
Fold in the whipped topping for a light, fluffy consistency. Chill in the refrigerator for 10 minutes.
Step 3: Assemble the Sandwiches

Spread or pipe a generous layer of pudding filling onto the flat side of one cookie.
Top with another cookie to create a sandwich. Roll the edges of the sandwich in crushed Nilla wafers for added texture.
Step 4: Add the Glaze (Optional)

Mix powdered sugar and milk to create a smooth glaze. Drizzle over the top of each cookie sandwich.
Step 5: Serve and Enjoy

Chill the sandwiches in the refrigerator for 30 minutes before serving for the best flavor and texture.
Enjoy these delicious bites of banana pudding heaven!