In a medium saucepan, whisk together the sugar, cornstarch, and salt.

In a separate bowl, whisk the egg yolks and add them to the sugar mixture.

Gradually add the milk, whisking constantly to prevent lumps.

Place the saucepan over medium heat and cook, stirring constantly, until the mixture thickens. This should take about 10-15 minutes. Make sure it doesn't boil.

Once thickened, remove from heat and stir in the vanilla extract and butter. Let it cool slightly.

Transfer to a container and chill in the fridge for a 2-3 hours or overnight. The pudding will thicken significantly.

Leave your whipped cream in the refrigerator right up until you are about to use it. Measure out the heavy cream, powdered sugar, and vanilla extract into a mixing bowl. You can adjust the amount of powdered sugar to your taste. If you prefer sweeter whipped cream, you can add a bit more, but be careful not to over-sweeten.

Begin beating the cream on low speed using a hand mixer or a stand mixer fitted with the whisk attachment. You can also do this by hand with a wire whisk, but it will require more effort and time.

As the cream thickens slightly, you can gradually increase the mixer's speed to medium. Continue to beat until you see medium peaks forming, about 5 to 7 minutes. Medium peaks means the cream is thickening, and when you lift the beaters, the cream will form gentle peaks with slightly softened tips. Don't beat much past this stage or you will make butter. If you accidentally over-whip the cream, and it looks heavy and curdled, pour in a little bit more cold heavy cream ( about 1 tbsp), and gently fold it in by hand with a spatula until it smooths out.

Chill until ready to use.

Mix half of the prepared whipped cream with the chilled pudding.

In a serving dish or a trifle bowl, start by placing a thin layer of pudding on the bottom.

Add a layer of sliced bananas and shortbread cookies on top of the pudding.

Pour about half of the pudding mixture over the banana and cookie layer.

Add another layer of shortbread cookies, followed by more sliced bananas.

Pour the remaining pudding mixture over the second banana layer.

Top with the remaining whipped cream.

If desired, use additional cookies and banana slices to decorate the top. To prevent exposed banana slices from tuning brown, cover them in lemon juice.

Chill for 1 hour then serve!