In a large mixing bowl add the milk and the instant vanilla pudding, mix well with a whisk then set in the refrigerator for 5 minutes to set up.
In the meantime, add the heavy cream, powdered sugar and vanilla extract to the bowl of a stand mixer and beat until stiff peaks form.
Choose 4 glasses, (I like to use my stem-less wine glasses for this). Spoon some vanilla pudding into the bottom of each glass.
Add a layer of banana slices.
Add the cream to a piping bag with a 1M tip and pipe a layer of cream on top of the banana slices.
Top with a layer of vanilla wafers.
Repeat with another two more layers (or whatever your glasses will fit).
Finish with a layer of cream on top. Decorate with some crumbled vanilla wafers.
Allow to sit in the refrigerator for 30-60 minutes before eating so that everything can come together.
Notes
Banana pudding can be very forgiving. There's no right or wrong way to layer this dessert, just whatever feels right. I like to use a piping bag for the cream just to keep it a little tidier. I tried spooning it in there and I was losing the prettiness in the glass.