Put the cream, ginger, 1/4 cup of the sugar, the vanilla, and salt in a medium saucepan and bring to a simmer over medium-high heat, stirring until the sugar dissolves. Cover, remove from the heat, and steep for 20 minutes.
Position a rack in the center of the oven and heat the oven to 350°F. Bring a kettle of water to a boil. Put twelve 4-oz. ramekins or teacups in a roasting pan or baking dish that's at least as deep as the ramekins.
In a medium bowl, whisk the yolks and 1/4 cup of the sugar until smooth and combined. Lightly whisk about 1/2 cup of the warm cream mixture into the yolk mixture and then gradually whisk in the remaining cream mixture. Stir rather than whip with the whisk—you don't want a frothy mixture, or the baked custards will have a foamy-looking surface. Strain the mixture through a fine sieve into a large Pyrex measuring cup or a heatproof bowl with a spout.
Divide the custard among the ramekins. Slowly pour hot water from the kettle into the baking pan (don't get any water in the ramekins) until it comes about two-thirds of the way up the sides of the ramekins. Carefully transfer the pan to the oven and bake until the custards are set around the edges but still slightly jiggly (like Jell-O) in the center, 30 to 35 minutes. Transfer the ramekins to a cooling rack and let cool at room temperature for 30 minutes. Then refrigerate the custards uncovered. Once the custards are refrigerator-cold, wrap each ramekin with plastic wrap. Refrigerate for at least 3 hours or up to 2 days before proceeding.
To serve, sprinkle 1-1/2 tsp. of the remaining sugar evenly over each custard. Wipe any sugar off the rim of the ramekins. Light a mini blowtorch and hold the flame 2 to 3 inches from the top of the custard, slowly gliding it back and forth over the surface until the sugar melts and turns a deep golden brown. Allow the sugar to cool and harden for a few minutes, and then serve immediately.
You can make and bake the custards up to 2 days ahead. Wrap them in plastic and refrigerate until ready to finish with the sugar.