Reduce orange juice to 1/4 cup by boiling.
Remove from heat.Cook cream and 1 cup sugar just until sugar melts.Preheat oven to 350f. and place one rack on top and one on bottom of oven.In large bowl, whisk cream mixture into egg yolks; then add Grand Marnier and reduced orange juice. Stir in orange peel and vanilla.
Pour evenly into 12 (3/4cup) ramekins; place 6 each ramekins into 2 baking pans and add boiling water to come halfway up ramekins.
Bake until custards are set in center, about 40 minutes. Cool, cover and chill overnight.Preheat broiler. On baking sheets, put ramekins and sprinkle each with 1 teaspoon brown sugar. Broil until sugar is melted and browned, about 2 minutes, taking care not to burn.
Source: Foodista