How to Make It
In a medium saucepan, stir 1 cup of the sugar with 3 tablespoons of water. Bring to a boil over moderate heat. Cook, swirling the pan occasionally, until an amber caramel forms, 6 to 8 minutes. Working quickly, pour the caramel into eight 8-ounce ceramic ramekins, swirling to coat the bottoms.
Preheat the oven to 325°. Line a small roasting pan with a double layer of paper towels and set the ramekins on the towels. In a large bowl, using a hand mixer, beat both cheeses with the remaining 1 cup of sugar at medium-high speed until very smooth, 1 to 2 minutes. Beat in the whole eggs and yolks one at a time until incorporated, then beat in the milk, heavy cream, vanilla and salt. Pour the custard into the prepared ramekins. Add enough boiling water to the roasting pan to reach halfway up the sides of the ramekins.
Loosely tent the pan with foil and bake the flans for about 50 minutes, until just set but still jiggly in the center. Using tongs, carefully transfer the ramekins to a rack and let the flans cool completely. Cover the ramekins with plastic and refrigerate for at least 2 hours or overnight.
Run a thin knife around each flan. Invert a plate over each ramekin, then turn the flan out onto the plate, shaking the ramekin gently if necessary. Serve immediately.