In a medium saucepan, combine the sugar and water over medium heat. Stir occasionally until the sugar dissolves.
Continue cooking without stirring until the mixture turns a deep amber color. Remove from heat.
Carefully pour the caramel into the bottom of a round baking dish, tilting the dish to spread it evenly. Set aside to cool and harden.
Preheat your oven to 350°F (175°C).
In a large bowl, whisk together the sweetened condensed milk, evaporated milk, eggs, and vanilla extract until well combined.
Pour the flan mixture over the set caramel in the baking dish.
Place the baking dish in a larger roasting pan. Add hot water to the roasting pan to come halfway up the sides of the flan dish, creating a water bath.
Bake in the preheated oven for 50-60 minutes, or until a knife inserted into the center comes out clean.
Remove the flan from the oven and let it cool in the water bath. Once cooled, refrigerate for at least 4 hours or overnight.
To unmold, run a knife around the edges of the flan. Place a serving plate over the dish and invert quickly to release the flan onto the plate.
Enjoy your meal!