Preheat oven to 325 degrees F. Place six 4-ounce ceramic ramekins in a large roasting pan, large enough to hold them without their touching. Set aside.
Place the ginger, sugar and lemon strips into the bowl of a food processor and pulse until chopped medium-fine. Transfer to a saucepan and let sit 10 minutes for the sugar to draw out the liquids from the ginger and lemon peel.
Stir the cream into the ginger mixture and place pan over medium-low heat. Bring to a full simmer, stirring frequently. Turn the heat off and cover the pan. Let sit and steep for 30 minutes.
Strain the cream through a fine mesh strainer and discard the solids. Place the yolks in a large bowl and whisk in the vanilla and salt. Slowly add the cream while whisking constantly. Whisk until completely blended.
Place the roasting pan as near to the oven door as possible and pour the custard into the ramekins, filling them full. Carefully pour hot tap water into the bottom of the roasting pan until it comes 2/3 up the sides of the ramekins.
Place roasting pan in oven and bake about 40 minutes, or until custards are barely jiggly in the center. Remove the ramekins from the water and cool on a wire rack. Once completely cool, wrap each ramekin in plastic and refrigerate until cold, at least 4 hours or up to 2 days.
When ready to serve, preheat oven to Hi-Broil. Sprinkle 1/2 tablespoon sugar evenly over the top of each custard and place ramekins onto a baking sheet. Place in oven on the top rack and watch carefully until the sugar is a deep golden brown on top. Remove from oven and let sit about 15 minutes until the sugar becomes a hard, crackly surface.