1. Preheat the oven to 325°F/165°C.
2. Have ready 6 flan molds or individual ramekins. Make sure they're plain with no ridges or patterns. You can use individual muffins or popover pans. 

For the caramel:

1. Place the sugar in a non-stick skillet. Add the water and swirl to moisten. 
2. Cook at medium-low heat. It will start to melt and bubble. The color will change as it cooks more, so swirl gently the pan to cook it more evenly. Don’t let it turn too dark or it will be bitter. 
3. Once the caramel is golden brown, divide it into the six molds, covering the bottoms before it solidifies. Let it firm up while you prepare the custard. 

For the flan mixture:

1. Blend the eggs well in a large bowl using a hand whisk (avoid an electric mixer as it will add a lot of air to your custard). 
2. Add the condensed milk, milk and vanilla extract, and whisk until well combined and integrated.
3. Place your molds inside a baking tray with at least 2-inch sides. 
4. Divide the mixture evenly between the prepared pans. You can strain it for a smoother flan. 

For the water bath:

1. Place the roasting pan or baking tray inside the preheated oven and slowly pour hot water from a jar. It might spit a little. 
2. Bake the individual flans for about 40-45 minutes, or until a toothpick inserted in the center of the flan comes out clean. Remove from the water bath and let them cool down to room temperature on a wire rack before refrigerating.
3. Cover with plastic wrap and refrigerate for at least 2 hours or overnight before removing. 

Remove the flans from the ramekins with care:

1. Run a smooth-bladed knife around the edges to loosen it. Place a serving plate on top of the flan mold, hold both tightly, and quickly invert them.
2. Gently lift the mold, allowing the caramel flan to release onto the plate. The caramel sauce will flow over the flan.
3. Serve them with sweetened whipped cream, dulce de leche or both.