In a bowl, beat together the evaporated milk, condensed milk, vanilla extract, egg whites, and whole eggs. Set aside.
In a small pot or sauce pan, on medium heat, heat the sugar until syrup-like and brown in color, about 8 to 10 minutes. Keep stirring the sugar, as it can burn easily. Immediately pour the melted sugar caramel into individual small ramekins (or a 9 by 13-inch baking dish), coating the bottom. Be quick, otherwise, the caramel will get hard.
Pour in the milk mixture.
Place the ramekins or the baking dish in a larger deep pan filled halfway up with water, but be sure not to let any water spill into the flan mixture. Bake in the oven for 45 minutes to 1 hour, or until the custard is set.
Let the custard cool 2 hours before serving. To serve, you can either use a knife, run through the side of the ramekin and flip it over on a plate or just serve in the ramekin.
Recipe by Let's Cook Some Food at https://www.letscooksomefood.com/caramel-flan/