Start with the caramel, in a pot add orange juice, sugar and let it turn into caramel then pour over your "flan molds" or Ramekins. let them get cold before you pour the batter onto it.
Flan
In a bowl add condensed, evaporated milk, eggs, salt, vanilla extract, yolks, orange zest and integrate.
Pass the batter trough a fine strainer( at least 4 times) the pour the batter on the Ramekins
Bake in a water bath at 325 F 162C for 40 min or until the center is almost cooked (not too runny)
Let them sit overnight on your fridge, then use a spatula to take them out of the ramekins and enjoy!
Notes
Custards such as flan, get harder as they get cold if the center is not runny they are done, let them cool down and they will have "the perfect consistency" otherwise you will overcook your flan.