Set your oven’s temperature to 375°F (190°C) to begin. In a medium mixing basin, combine the salt, baking soda, baking powder, and flour. The softened butter, granulated sugar, and brown sugar should be well combined in a different, larger basin.

Mix in the egg and vanilla extract thoroughly after adding them. Gradually add the dry flour mixture to the wet ingredients, stirring until the dough forms.

Now, fold in the mashed bananas, crushed vanilla wafers, and chopped walnuts (if using) until they are evenly distributed in the cookie dough.

Prepare the banana pudding filling in a separate bowl by whisking together the instant banana pudding mix and cold milk. Let it sit for a few minutes until it thickens. Once thickened, gently fold in the whipped cream until you have a smooth and creamy mixture.

Scoop tablespoon-sized portions of cookie dough onto a baking sheet lined with parchment paper. Leave enough space between each cookie to allow for spreading. Flatten the dough slightly with the back of a spoon.

Bake the cookies for about 10-12 minutes or until they turn golden brown around the edges. Remove them from the oven and let them cool on a wire rack.

Once the cookies have cooled, take one cookie and spread a generous amount of banana pudding filling on the flat side. Top it with another cookie to create a delicious sandwich.