Nutrition per serving may change if servings are adjusted.
2 tablespoons water plus ½ cup, divided
1 envelope unflavored gelatin
2 cups half-and-half
¾ cup sugar plus 5 tablespoons, divided
3 cups buttermilk
Pinch of salt
1½ cups sliced rhubarb ( ½ inch)
½ teaspoon freshly grated orange zest
2 tablespoons orange juice
½ vanilla bean, split
Place 2 tablespoons water in a large, heatproof mixing bowl and sprinkle with gelatin; let stand about 5 minutes to soften. If some of it still seems dry, sprinkle with a few more drops of water.
Heat half-and-half and ¾ cup sugar in a medium saucepan over medium heat until steaming, stirring to dissolve the sugar. Pour over the gelatin and whisk vigorously to dissolve. Whisk in buttermilk and salt. Pour the mixture through a fine sieve to strain out any lumps. Divide among eight 1-cup dessert cups or ramekins. Loosely cover and refrigerate for at least 8 hours or up to 2 days.
Preheat oven to 400°F.
Place rhubarb in a medium glass or ceramic baking dish. Combine the remaining ½ cup water and 5 tablespoons sugar, orange zest and juice in a small saucepan. Scrape the seeds from the vanilla bean into the mixture and add the bean to the pan. Bring to a boil, stirring to dissolve the sugar. Pour the syrup mixture over the rhubarb.
Bake, uncovered, until the rhubarb is tender, about 20 minutes. Let cool for 30 minutes, then cover and refrigerate until cold, at least 1 hour and up to 1 day.
To serve, remove the vanilla bean from the sauce and discard. Top each panna cotta with about 2 tablespoons of the sauce.
Make Ahead Tip: Refrigerate panna cotta for up to 2 days. Refrigerate sauce for up to 1 day.
227 calories;8 g fat(5 g sat); 0 g fiber; 35 g carbohydrates; 6 g protein; 9 mcg folate; 26 mg cholesterol; 34 g sugars; 27 g added sugars; 287 IU vitamin A; 5 mg vitamin C; 191 mg calcium; 0 mg iron; 220 mg sodium; 291 mg potassium
Carbohydrate Servings: 2½
Exchanges: 2 other carbohydrate, ½ low-fat milk, 1½ fat