6 large egg yolks
1/4 (50 g) cup white sugar, plus 2 tablespoons (25 g) for the tops
1/4 (2 g) teaspoon salt
1 tablespoon (15 ml) vanilla extract
4 cups (960 ml) heavy cream
fresh berries for serving
Whisk together yolks, 1/4 cup sugar, salt, vanilla and cream in a medium bowl. Strain through a mesh sieve into a liquid measuring cup.
Line bottom of a 7-quart or larger oval slow cooker with a folded kitchen towel to create a non-slip surface so ramekins won't slide around. Space 6 (4-ounce) ramekins even on towel. Fill slow cooker with enough water to come halfway up sides of ramekins.
Pour custard evenly into ramekins. Cover each ramekin with a piece of foil, then cover slow cooker with lid. Cook on low until custard is set but still wiggles, about 2 hours.
Remove foil and set ramekins on a wire rack to cool for 45 minutes, then transfer to refrigerator to chill, uncovered for 3 hours.
Before serving, remove ramekins from fridge. Preheat the broiler. Sprinkle each ramekin with an even 1 teaspoon coating of sugar. Broil (or brulee with a kitchen torch) to caramelize sugar.
Return to refrigerator for at least 15 minutes before serving topped with fresh berries.