Place water and 150g sugar in a saucepan over high heat and allow to become a deep golden caramel colour.
In a separate saucepan, add milk and 80g sugar. Warm the milk until the sugar has dissolved, but don’t allow the milk to get too hot or to boil.
Whisk the eggs lightly in a large bowl and then slowly incorporate the tepid milk mixture into the eggs and whisk for a couple of minutes. Give the bowl a good tap on the bench to remove some of the bubbles.
When the caramel has turned a deep golden colour carefully add ½ cup of water and shake to combine (this stops the caramel from setting).
Pour caramel over the base of a cake tin, rolling around to make sure you have an even coverage across the bottom and the edges.
Gently pour the milk and egg mixture over the caramel.
Place the cake tin in a larger roasting tin with enough water to come halfway up the sides of the cake tin (a bain marie).
Bake for 45 – 60 minutes, or until it is set.
When it is cooked remove from the oven and leave to cool for 2 hours before serving, alternatively you can refrigerate it and serve the next day.