01 - Preheat the oven to 325°F. Boil water in a kettle for the water bath.
02 - Combine whole milk and heavy cream in a medium saucepan. Warm over medium heat until steaming but not boiling, then remove from heat.
03 - In a mixing bowl, whisk together the egg yolks, whole eggs, granulated sugar, vanilla extract, and salt until fully blended and slightly thickened.
04 - Gradually whisk the warm milk and cream mixture into the egg blend to avoid curdling.
05 - Pass the combined mixture through a fine-mesh sieve into a large container to ensure smooth texture.
06 - Divide the strained custard evenly among four ramekins.
07 - Place ramekins in a deep baking dish. Pour hot water until it reaches halfway up the ramekin sides. Bake for 30 to 35 minutes until custards are set with slight wobble in the center.
08 - Remove ramekins from the water bath and cool to room temperature. Refrigerate at least 2 hours before serving, if preferred.