01 - Preheat the oven to 325°F. Bring a kettle of water to a boil.
02 - In a medium saucepan, combine whole milk and heavy cream. Warm over medium heat until steaming but not boiling, then remove from heat.
03 - In a large mixing bowl, whisk together the eggs, granulated sugar, vanilla extract, and salt until combined thoroughly without frothing.
04 - Slowly whisk the warm milk mixture into the egg mixture in small increments to temper the eggs.
05 - Pour the combined mixture through a fine sieve into a large measuring jug to remove any solids.
06 - Divide the custard evenly into four ramekins, each holding 6 ounces.
07 - Place the ramekins inside a deep baking dish. Carefully pour boiling water into the dish until it reaches halfway up the sides of the ramekins.
08 - Transfer the baking dish to the oven and bake for 35 to 40 minutes, or until the custards are just set with a slight wobble in the center.
09 - Remove ramekins from the water bath and allow to cool to room temperature. Refrigerate for at least 2 hours before serving.