Preheat the oven to 350°F (175°C).
In a saucepan over medium-low heat, melt the granulated sugar, stirring occasionally, until it turns into a golden caramel.
Quickly pour the caramel into a 9-inch cake pan, tilting to coat the bottom evenly. Let it cool and harden.
In a blender, combine the sweetened condensed milk, evaporated milk, eggs, vanilla extract, and salt. Blend until smooth.
Pour the custard mixture over the hardened caramel in the cake pan.
Place the cake pan inside a larger baking dish and fill the outer dish with hot water, creating a water bath.
Bake for 50-55 minutes, or until the center is just set and slightly jiggly.
Remove from the oven and let cool to room temperature, then refrigerate for at least 4 hours or overnight.
Run a knife around the edges of the flan and carefully invert onto a serving plate to release the caramel sauce.
Slice and serve chilled.