Prepare the Caramel: Melt sugar in a medium saucepan over medium heat until golden. Quickly pour into a round baking dish, swirling to coat.
Mix the Custard: In a blender, combine evaporated milk, sweetened condensed milk, eggs, egg yolks, vanilla, and salt; blend until smooth. Pour over the caramel in the baking dish.
Bake the Flan: Preheat oven to 350°F (175°C). Place the filled baking dish in a larger pan and add hot water halfway up the sides. Bake for 50-60 minutes or until slightly jiggly in the center.
Cool and Serve: Let cool in the water bath for 30 minutes, then refrigerate for at least 4 hours or overnight. To serve, run a knife around edges before inverting onto a plate.
