Preheat oven to 300 degrees – and bring a large kettle of water to a boil.
Put milk, cream, dulce de leche (milk caramel), and a little more than half of sugar in a heavy saucepan – set aside on a low flame, stirring/scraping the bottom regularly with a heat-resistant rubber or wooden spatula.
In a small but heavy saucepan, add the remaining sugar and 1 tablespoon water. Cook over medium high heat, caramelizing to a dark golden color, and then immediately transfer the hot caramel to the bottom of a large flexible mold, pie tins, or 12 smaller tins or molds. Take great care, the caramel is very VERY hot!
Bring the milk mixture to a boil, stirring constantly – remove from heat. Beat the eggs and yolks well, and temper into the hot milk; adding little by little while vigorously whisking – too fast and you get scrambled eggs. Strain the custard into prepared molds.
Pour custard into awaiting pie tins, cover with foil, place in roasting pan, and finally place in the center of a preheated oven. Carefully add boiling water to the roasting pan, filling it half way up the sides of the mold. Bake until custard sets, test by jiggling pan – about 50-60 minutes for one large flan, cooking time depends on conditions.
Cool or chill and serve, turning the flan over onto a plate and removing mold. If flan is cold, dip in hot water to loosen from the mold.
