Preheat your oven to 350 degrees F.

In a small, heavy saucepan, melt the sugar over medium heat. Stir occasionally, until the sugar dissolves and turns a golden brown. Pour this caramel into a 9-inch round baking dish, tilting to coat the bottom evenly.

In a blender, combine the heavy cream, sweetened condensed milk, eggs, whole milk, and vanilla extract. Blend for about one minute or until well mixed.

Carefully pour the cream mixture over the caramel in the baking dish.

Place the baking dish into a larger roasting pan. Pour boiling water into the roasting pan until it reaches halfway up the sides of the baking dish, creating a water bath.

Bake in the preheated oven for 50 to 60 minutes, or until the flan is just set (it should jiggle slightly when shaken).

Remove the flan from the oven and water bath, then let it cool to room temperature. Chill in the refrigerator for at least 4 hours before serving.

To serve, run a knife around the edges of the flan, then invert onto a serving plate, allowing the caramel to flow over the flan.