Preheat the oven to 280°F
Place 6 small ramekins in a deep baking dish
In a saucepan, combine the cream, milk, sugar, vanilla, and salt. Heat gently, stirring, until the sugar is dissolved. Do not boil.
Remove from the heat and let the mixture cool until lukewarm.
Place the egg whites in a bowl and stir or whisk very gently just until loosened. Do not whip or incorporate air.
Slowly pour the cooled cream mixture into the egg whites while stirring gently.
For the smoothest texture, strain the mixture through a fine-mesh sieve.
Divide among the ramekins.
Pour hot water into the baking dish until it reaches about halfway up the sides of the ramekins.
Bake for ~40 minutes, or until the custards are just set around the edges but still have a gentle wobble in the center with an internal temperature around 160–163°F
Remove the canning jars from the water bath and let cool to room temperature
Cover and refrigerate for at least 4 hours, preferably overnight
Serve chilled in the canning jars topped with salted caramel, macerated strawberries, and whipped cream (recipes below)