In a blender, add the banana and milk, and blend until smooth. Pour the banana milk through a fine mesh sieve into a small saucepan, weighing it out to 227g (1 cup).

Place the saucepan over low-medium heat and bring the milk to a simmer, or about 190 degrees F.

Meanwhile, in a medium bowl, vigorously whisk together the egg yolks, granulated sugar, and cornstarch until pale in color and the mixture flows off of the whisk.

Once the milk has reached a simmer, slowly pour half of it into the egg-sugar mixture while simultaneously whisking to temper the eggs. Pour everything back into the saucepan and place over medium heat. Use a rubber spatula to mix constantly as it thickens.

Once the pastry cream is thick and a few big bubbles come to the surface, continue whisking for one more minute, then remove the pan from heat.

Immediately pour the pastry cream through a fine mesh sieve into a small bowl to ensure it’s perfectly smooth. Then, mix in the butter and vanilla with a rubber spatula.

Press plastic wrap up against the surface of the pastry cream to prevent a skin from forming, and place in the fridge to chill for at least one hour or until ready to use.

Just before you are ready to assemble the pudding, make the whipped cream.

In a medium bowl, beat the heavy cream with an electric mixer while slowly pouring in the granulated sugar.

Beat until soft peaks form, and no more! It can be easy to over-whip, so watch carefully.

Add ¼ (or 113g) of the whipped cream to the cooled pastry cream, and gently fold with a rubber spatula until fully combined. Reserve the remaining whipped cream for assembly.

In a large glass dish, layer the pastry cream, whipped cream, and Nilla wafers. Finish with a few Nilla wafers on top. Chill the banana milk pudding in the fridge overnight before serving.