In a medium saucepan, combine the heavy cream, whole milk, egg yolks, brown sugar, and salt.
2 cups heavy cream, 1 cup whole milk, 5 large egg yolks, 1 cup light brown sugar, ¼ teaspoon salt
Heat over medium, stirring constantly, until the mixture thickens slightly, about 8 to 10 minutes. It should coat the back of a spoon.
Remove from heat and stir in the vanilla extract.
1 tablespoon vanilla extract
Pour the custard through a fine mesh strainer into a heat-safe bowl.
Cool the custard in an ice bath for 30 to 60 minutes, then cover with plastic wrap touching the surface. Refrigerate for 2 to 4 hours until fully chilled.