Preheat the oven to 350°F (175°C).
In a bowl, combine graham cracker crumbs, melted butter, and sugar. Mix until well combined.
Line a muffin tin with cupcake liners and press about a tablespoon of the crumb mixture into each liner.
Bake for 5-7 minutes, then let cool completely.
In a saucepan, whisk together milk, sugar, cornstarch, and egg yolks. Cook over medium heat, stirring constantly, until the mixture thickens and comes to a gentle boil.
Remove from heat and stir in butter and vanilla extract.
Let the custard cool, then fold in sliced bananas.
Spoon the banana custard into the prepared crusts, filling each to the top.
Chill the filled cupcakes in the refrigerator for at least 2 hours to set.
In a bowl, whip the heavy cream with powdered sugar and vanilla extract until stiff peaks form.
Pipe or spoon the whipped cream over the chilled custard filling.
Decorate with banana slices and a drizzle of caramel sauce.
Serve immediately or store in the refrigerator until ready to serve.
