Preheat the oven to 160°C (325°F) and place a roasting pan filled with about 2cm of hot water in the oven. This will be used later for baking the creme caramel.
In a saucepan, combine 150g granulated sugar and 6 tablespoons of water. Heat the mixture over medium heat, stirring occasionally, until the sugar dissolves.
Stop stirring and let the mixture cook until it turns golden brown, which should take about 5-6 minutes. Be careful not to burn the caramel.
Remove the saucepan from the heat and quickly pour the caramel into a 9 inch baking dish, swirling it around the sides. Set the dish aside to cool.
In a mixing bowl, whisk together 6 eggs, 800ml whole milk, 2 tsp vanilla extract, and 200g granulated sugar until well combined.
Pour the mixture through a sieve into a jug, then pour it into the prepared baking dish.
Carefully place the baking dish into the roasting pan filled with hot water in the oven.
Bake for 50-60 minutes or until the custard is set around the edges but still slightly wobbly in the center.
Remove the baking dish from the roasting pan and let it cool.
Once cooled, cover the baking dish with cling film and chill in the fridge for at least 2 hours or overnight.
To serve, run a knife around the edge of the baking dish and invert it onto a large serving plate. The caramel should be on top and drizzle down the sides of the custard.
Slice the creme caramel into portions and serve. Enjoy!