Make the caramel first by dissolving 1/2 cup granulated sugar over low/medium heat. Leave alone, swirling occasionally to ensure the sugar does not harden and/or burn (see post for tips). Once it turns a light golden colour, remove from heat and spread evenly on your baking pan (see notes). Set aside and work on the flan.
Whisk the 10 egg yolks before adding the can of condensed milk. Stir until thoroughly combined. Add 1 cup evaporated milk, 1 teaspoon vanilla extract and 1/2 teaspoon fresh lime juice and mix well. Add a pinch of salt and give the mixture a final stir.
Transfer your mixture into your baking pan (on top of the caramel) by straining it through a fine mesh sieve or a cheese cloth. Gently and carefully pour it so as not to create any air bubbles.
Place your baking dish in a roasting pan and put the roasting pan in your preheated oven. Then fill the roasting pan with hot water until it reaches halfway up the side of your baking pan. Bake for 30-45 minutes or until the flan is set (firm but still jiggly; see post). If you see that the top is getting too brown, loosely cover with aluminum foil and continue baking.
Take the flan out of the oven and cool slightly before refrigerating for at least 3 hours.
Run a sharp knife around the edges of your pan to loosen the flan before inverting into a platter to serve (see notes).
Leche flan is traditionally made with dayap, a local key lime variety. If you can get hold of that, use it. Otherwise, lime juice works just fine.
It is also traditionally baked in a llanera which is an aluminum mold/baking pan but thinner. I use an 8x8 baking pan. If you want thicker leche flan, use a smaller pan but make sure to adjust the baking time.
I sometimes have issues getting the flan out of the baking pan. So if I’m not serving it to company I don’t bother inverting it into a serving platter; we just scoop it out and eat it rustic style. It tastes just as great. But if you do have company and your edges are all uneven as a result of your attempts to take it out of the dish don’t worry – just slice the edges off or slice them into bite-size pieces. Nobody will ever know. The serving size of 24 is based on cutting the 8x8 inch flan into bite-sized squares. This dessert is very rich so a little goes a long way.