Preheat oven to 160 degrees C. Lightly grease four 1-cup (250ml) capacity soufflé dishes. Place in a large baking dish.
Combine 2/3 cup (150g) of the sugar and ½ cup (125ml) water in a medium saucepan over low heat. Cook, stirring, without boiling, until sugar dissolves. Increase heat to medium-high. Bring to the boil. Boil, without stirring, for 5-7 minutes or until mixture is a deep caramel colour. Remove from heat and allow bubbles to subside. Pour toffee into prepared dishes.
Whisk the eggs and remaining sugar in a large bowl. Stir the coffee and 2 tablespoons boiling water in a small saucepan over medium heat until dissolved. Stir in cream and milk and bring to the boil. Whisking constantly, pour hot milk mixture into egg mixture. Strain mixture into a jug. Pour into dishes.
Add enough boiling water in baking dish to come half way up side of dishes. Bake for 25-30 minutes or until just set. Remove crème caramels from baking dish. Cool for 10 minutes. Cover. Place in fridge for 6 hours or until cold.
Gently run a sharp knife around the edge of crème caramels. Invert onto serving plates. Serve.