In a pot, add in sugar, water, lemon juice and cook on medium heat until they turn amber color. Leave untouched.

Very carefully pour the caramel into a 3x9 inch bread loaf pan. Using a brush, coat the insides of the pan with the caramel. The coat helps to make it easier to release the flan later. Set aside.

In a bowl, add in eggs, condensed milk, milk and vanilla extract. Gently whisk everything together just until combined. Do not whisk vigorously, creating foams will result in the texture of the flan not being smooth. Sift into a jar.

Place the pan with caramel in a container for bain-marie. Pour in the sifted mixture into the pan with caramel and cover with aluminium foil. This is to prevent crust forming on top. Add hot water until ¾ of container's height.

Bake at 150ºC (300ºF) preheated oven for 1 hour 20 minutes or until fully cooked. Use upper and lower heat. To check if it's done, insert a knife into the flan. it should come out clean. Remove from the bain-marie container and leave to cool completely. Wrap with cling film and chill in the fridge overnight before serving.