Heat the milk and vanilla in a pan until steaming. Whisk the egg yolks and sugar in a large bowl until smooth and creamy. Continue whisking while you pour the hot milk over the egg yolks in a steady stream, until combined. Transfer back to the pan, and heat over a medium-low heat, stirring constantly, until thickened, about 10 mins. It shouldn’t be custard thick, more of a thick double cream consistency. Transfer to a bowl, cover the surface with a scrunched piece of baking parchment and leave to cool. Once cool, chill until ready to serve.
Put the egg white in a stand mixer. Whisk for 4-5 mins until you get soft peaks. With the motor still running, add the sugar 1 tbsp at a time, allowing it to be incorporated before adding the next. When all the sugar has been added, whisk for another 2-3 mins until stiff.
Pour the milk and 200ml water into a wide pan or medium frying pan and heat until steaming, but not boiling. Add heaped teaspoons of the meringue mix into the milk, using another teaspoon to slide the meringue off the spoon, and gently poach for 3-4 mins (you don’t need to move them around). Carefully turn the meringues over and cook the other side for 3-4 mins until set. Remove the meringues from the milk and leave to cool on a plate.
To make the caramel, heat the sugar, 1 tbsp water and pinch of salt in a small pan and cook on a medium heat until you get a lightly golden caramel, about 10 mins. Keep warm for drizzling at the end.
To serve, briefly stir, then spoon the custard into four ramekins or small bowls. Top each with a meringue and a drizzle of caramel.