Beat all of the creme ingredients together in a mixing bowl.
For the caramel, heat up sugar in a saucepan, stirring to dissolve the sugar and leave to caramelise on med/ high heat for about 5 minutes. Test if the caramel hardens by placing a teaspoonful on the tart dish, it should tap hard, if not, continue to cook.
Once the caramel is ready, pour a thin layer into the dish and swirl very quickly (as it will harden) and leave to set hard.
Pour the creme mixture into dish and place on a large baking tray of boiling water (bain-marie).
Bake for about 30 minutes. leave to cool and refrigerate for at least 6 hours or overnight.
To serve, loosen the custard with a thin knife around the sides, turn the dish upside down onto another plate and tap out the baked creme caramel. The caramel should drizzle down the sides, forming a caramel puddle.