6 tbsp. palm sugar (finely grated) or light brown sugar
Preheat oven to 300°.
Whisk egg yolks and sugar in medium bowl.
Combine cream, lime rind, and ginger powder in medium saucepan and bring to a boil; gradually whisk hot cream mixture into egg mixture.
Place bowl over medium saucepan of simmering water. Whisk over heat about 10 minutes. Divide custard among six, 3⁄4-cup ovenproof ramekins or dishes.
Place ramekins in large baking pan. Pour enough boiling water into baking pan to come halfway up side of ramekins.
Bake 20–25 minutes, or until custard just sets.
Remove ramekins from water and place on a wire rack to cool completely.
Cover each ramekin with aluminum foil and refrigerate 3 hours or overnight.
Just before serving, remove foil from each custard and evenly sprinkle surface with 1 tablespoon of palm sugar or brown sugar. Caramelize top of each custard with blowtorch, aiming flame over sugar until it melts and browns, about 2 minutes.