In a medium saucepan, whisk together the whole milk, granulated sugar, cornstarch, and salt until smooth. Place the saucepan over medium heat and continue whisking until the mixture starts to thicken, about 5 to 7 minutes. Remove from heat and let it cool slightly.

In a separate bowl, whisk the large egg yolks until pale and frothy. Gradually add a small amount of the warm milk mixture while whisking to prevent scrambling. Return this mixture to the saucepan and cook over medium heat for an additional 2 to 3 minutes.

Remove the saucepan from heat and stir in the unsalted butter, vanilla extract, and banana extract, if using. Stir until melted and incorporated. Transfer to a bowl, cover with plastic wrap, and chill in the refrigerator for at least 2 hours.

Once chilled, gently fold in the whipped topping until well combined.

Brew a strong cup of coffee and let it cool. Stir in banana liqueur or rum if desired. Pour into a shallow dish for soaking the ladyfingers.

Slice the ripe bananas thinly and toss with lemon juice. Dip ladyfingers briefly in the coffee soak and layer them at the bottom of your serving dish.

Spread half of the creamy pudding over the ladyfingers and add half of the sliced bananas on top.

Repeat layering with another round of coffee-soaked ladyfingers, the remaining pudding mixture, and the final layer of banana slices.

Cover with plastic wrap and refrigerate for at least 4 hours, preferably overnight.

Before serving, dust generously with unsweetened cocoa powder, slice, and enjoy!