- 4 egg yolks
- 1/4 cup white sugar
- 1/4 teaspoon salt
- 1 2/3 cups heavy whipping cream
- 2 teaspoons vanilla extract
- 4 teaspoons white sugar
- Whisk yolks with 1/4 cup sugar and salt in a bowl until smooth; gently whisk in cream and vanilla extract. Strain custard mixture into a liquid measuring cup.
- Line bottom of a 6-quart oval slow cooker with a folded kitchen towel to create a level surface so ramekins won't slide around. Set four 4-ounce ramekins on the towel. Fill slow cooker with enough water to come halfway up sides of ramekins.
- Pour custard evenly into ramekins. Drape paper towels over top of slow cooker liner to absorb any condensation during baking; cover with lid to secure.
- Cook on Low until custard is set but jiggles slightly, about 2 hours.
- Transfer ramekins to a rack to cool completely, about 45 minutes. Refrigerate custards, uncovered, until cold, at least 3 hours.
- Sprinkle 1 teaspoon sugar over each ramekin and shake gently to distribute evenly. Heat the sugar using a culinary torch until melted and browned, about 1 minute.