Prepare the Cheese Mixture: Preheat your oven to 160°C (320°F).
In a large mixing bowl, combine the cream cheese, grated cheddar, and parmesan cheese. Add the eggs, cornflour, mustard powder, Worcestershire sauce, and salt. Mix until well combined.
Heat the Milk: In a saucepan, gently heat the milk until it is just about to simmer. Be careful not to let it boil.
Gradually add the hot milk to the cheese mixture, whisking continuously to create a smooth custard base.
Bake the Custard: Pour the custard mixture into a greased baking dish or individual ramekins.
Place the dish or ramekins in a larger baking pan and fill the pan with hot water until it reaches halfway up the sides of the custard dish.
Bake in the preheated oven for 30-35 minutes, or until the custard is set and slightly golden on top.
Serve: Remove the custard from the oven and let it cool slightly.
Garnish with a sprinkle of paprika and fresh herbs before serving.
Serve warm as a side dish or appetizer.