In a medium bowl, whisk together the beaten egg yolks, sugar, cornstarch and salt....it will be pretty lumpy, but that's fine. Set it aside. Place the milk and cream into a large pot over medium heat. Let it heat to a simmer, stirring often, but do not let it come to a boil. Once it begins to simmer, remove it from the heat.
Slowly add in 1 cup of the heated milk into the egg yolk mixture while whisking constantly to temper the eggs. Once it's all whisked together, whisk the egg mixture back into the pot of heated milk and return it to the burner. Now, cook this mixture over medium heat for 8-10 minutes, stirring nearly constantly, until it is nice and thick.
Once thickened, remove the pot from the heat and immediately stir in the butter. Once it's melted in, stir in the vanilla extract. Now run the pudding through a fine mesh sieve with a rubber spatula to remove any lumps and to get the smoothest pudding.
At this point, either keep it in the bowl you strained it into or separate it into individual serving cups. Either way, you're going to cover the pudding with plastic wrap. You want to press the plastic wrap lightly onto the surface of the pudding, to prevent a skin from forming.
Let it chill in the fridge for at least 2 hours before serving. Then eat it plain or top with some yummy toppings (pictured here with chocolate curls and banana slices). It'll last up to 3 days in the fridge.
