make the caramel
Preheat your oven to 160 °C / 320 °F. Make the caramel. Add sugar, water and lemon juice to a saucepan. Place over medium-low heat and cook until the sugar dissolves into a beautiful, golden-brown caramel. It will take about 3 - 5 minutes. Don't stir, but keep an eye on it. Pour the caramel into a small baking dish (approx. 20 cm x 10 cm and 7 cm height or 8-inch x 4-inch x 3-inch height) Set aside for the caramel to set, approximately 10 - 15 minutes. The caramel has to harden.
vanilla cream (creme caramel)
Make the vanilla cream. In a bowl beat the eggs, egg yolks, sugar, pinch of salt, and rum using a hand whisk. Bring heavy cream, milk, and vanilla seeds to a boil in a saucepan. While beating the eggs, pour the heavy cream mixture over the egg mixture in a bowl. Whisk well to get a smooth texture. Strain the mixture through the sieve and pour over the hard caramel in a baking dish. Transfer the baking dish with the creme caramel to a large, deep baking pan and place in the preheated oven on the middle rack. Pour hot, boiling water into the larger baking dish until it comes one-half of the way up the side of the smaller baking dish (make sure not to splash water into the cream caramel). Bake for 1 hour and 15 minutes at 160 °C / 320 °F.
place in the fridge
Remove the baked flan with the larger baking dish from the oven. Leave the baked flan to set in the water bath until it comes to room temperature. Then cover the creme caramel with cling film and place in the fridge for at least 8 - 12 hours to set and cool completely.
Remove the creme caramel from the fridge. Run a small, sharp knife around the edge of the baking dish to loosen the custard. Place a serving plate on top of the custard and quickly invert it onto a plate. Cut on slices and serve.TipFor easier removal of the custard, dip the baking dish one-half of the way up the side with the creme caramel in hot boiling water for 10 seconds. Be careful not to splash water into the custard. This way it will be easier to invert it one a plate. You can use a blow torch as well.