Scald the milk in a large pot on the stove top over medium heat (or in the microwave), until it is almost boiling.

In a large sauce pan, combine the cornstarch, sugar, and salt.

Over medium-low heat, slowly add in the milk about ½ cup at a time while whisking constantly.

As the filling begins to thicken, add in another ½ cup of milk and continue whisking.

Once all of the milk is added and the filling has thickened (enough to coat the back of a spoon), remove the pot from the heat.

Pour about ½ cup of the filling into a glass measuring cup and then slowly drizzle it into the beaten egg yolks, whisking constantly until fully combined and smooth.

Pour the egg mixture back into the pot with the rest of the filling and cook for an additional 2-3 minutes or until the filling has thickened to a pudding consistency.

Stir in the butter and vanilla extract (and banana extract if using) until smooth.

Pour the pudding through a fine mesh strainer to remove any lumps.

Transfer to a bowl and cover with plastic wrap (place the plastic wrap directly on the surface of the vanilla pudding so a film doesn't form). Chill for at least 1 hour! Store in the fridge for up to a week.

In the bowl of a stand mixer fitted with the whisk attachment, or in a large mixing bowl using an electric hand mixer, combine the heavy whipping cream, powdered sugar, and vanilla.

Whip the mixture until it starts to thicken and stiff peaks form.

To keep the banana slices from turning brown, gently toss in a little bit of lemon juice for a few minutes.

Place 3-4 mini vanilla wafer cookies at the base of each jar or cup. Then spoon a small layer of pudding over top. Layer 4-5 banana slices over the pudding and top with a layer of whipped cream. Repeat the layers until you reach the top of the jar!

Let the pudding cups chill for about 2 hours before serving so that the nilla wafers can soften slightly.