Preheat your oven to 350°F (175°C).In a large bowl, whisk or blend eggs, evaporated milk, sweetened condensed milk, vanilla extract, and salt until smooth. For an extra smooth texture, strain the mixture through a fine-mesh sieve to remove air bubbles.
Pour the custard mixture over the hardened caramel in the baking dish. Place the dish inside a larger roasting pan, then carefully pour hot water into the roasting pan until it reaches halfway up the sides of the flan dish.
Bake for 50-60 minutes or until the flan is set but slightly jiggly in the center.
Remove the flan from the water bath and let it cool to room temperature. Refrigerate for at least 4 hours or overnight for best results.
To serve, run a knife around the edges of the flan, place a plate over the baking dish, and flip it over to release the caramel sauce on top.