1½ cups sugar
1 cup heavy cream, warmed
4 tbsp. salted butter*, at room temperature
½ tsp. sea salt
2 cups whole milk, divided
5 large egg yolks
1 tsp. vanilla extract
Add the sugar to a medium saucepan in an even layer. Heat over medium until the sugar at the edges of the pan begins to melt. Use a heatproof spatula to stir the melted sugar from the bottom and the edges to the center, until all the sugar is dissolved. Continue to cook, stirring occasionally, until the caramel reaches an amber color (test a drop on a white plate if needed). When the caramel reaches the correct color, immediately remove it from the heat. (Be vigilant here! Caramel can go from perfectly cooked to burnt in seconds – it is no fun when that happens, trust me!)
Add a bit of the cream in a slow drizzle down the inside edge of the pan, whisking to incorporate before adding more. If done slowly enough with warm cream, this can help prevent the mixture from seizing. Whisk in the butter. If the mixture has seized, don’t worry – just return the pan to the burner over low heat and stir gently, breaking up lumps as well as you can. If you can’t get rid of them all, it’s okay. Whisk in the salt and 1 cup of the milk.
Place the egg yolks in a medium bowl or liquid measuring cup (my preference) and whisk to blend. Slowly pour a bit of the warm caramel mixture into the bowl with the eggs, whisking constantly to prevent curdling. Continue until most of the caramel has been mixed in. Return the custard to the saucepan over medium-high heat. Continue to cook, stirring constantly and scraping the bottom of the pan to prevent burning, until the mixture thickens slightly and coats the back of a spoon (about 170˚-175˚ F).
Pour the custard through the mesh strainer into a bowl or storage container. Stir in remaining 1 cup of milk and the vanilla. Let cool slightly, then cover and refrigerate until completely chilled. Freeze in an ice cream maker according to the manufacturer’s instructions.
*If using unsalted butter, increase the sea salt to ¾ tsp.