Preheat oven to 300°F (150°C). Move rack to the lowest level.

Whisk together egg yolks, ¼ cup white sugar, and vanilla in a heatproof bowl.

Heat cream in a saucepan over medium-low until it begins to simmer.

Temper eggs by slowly whisking hot cream into the egg mixture, a little at a time.

Use a double boiler: Place bowl over simmering water, stir until mixture thickens and coats the spoon.

Pour custard into ramekins and place them in a rimmed baking dish.

Bake for 20–30 minutes until set with a slight jiggle.

Refrigerate for 2 hours.

Mix white and brown sugar for topping, sprinkle on cold custard.

Broil or torch sugar topping for 2–3 minutes until caramelized.

Chill 15 minutes, then serve.