Preheat oven to 350°F. Have your 2 quart oven-proof glass dish or mold on standby since you will have to move quickly with the caramel.
In a small, heavy saucepan, cook ½ cup of dry sugar over medium high heat until starting to bubble. Cook for about 3-5 minutes, stirring frequently, until it is light amber in color, careful not to burn {which can happen very quickly, so remove from heat as soon as the color gets to where you want it}.
Quickly and carefully pour caramel into oven-safe dish and swirl to coat the entire bottom and a little of the sides. Set aside to harden.
In a small saucepan over medium heat, stir together cream and ½ cup sugar until steaming, but not boiling, stirring to dissolve sugar. Remove from heat. Add vanilla extract.
In a mixing bowl, combine eggs, orange juice, orange zest, and salt, and whisk until smooth and lightened in color. Slowly add the cooled cream mixture a little at a time, and stir until completely incorporated.
Prepare a water bath - Place your baking dish in a roasting pan or another larger pan. Fill with lukewarm water until about ⅔ of the way up the sides of the baking dish {careful not to get any water in your dish}. Using a fine mesh strainer, pour egg and cream mixture into baking dish. Discard solids.
Bake for 1 hour or until the tip of a knife or a toothpick inserted in the center comes out clean. (Will still be jiggly, but set.) Remove from oven and allow to come to room temperature. Cover and refrigerate until cold.
To unmold: Run a knife along edge of dish. Place a serving dish or platter upside down on top. Quickly invert (over a sink, preferably, so you don't cover your kitchen in syrup). Garnish with orange if desired.