Greek Yogurt Panna Cotta with Strawberry-Rhubarb Sauce

To make the sauce: Put the rhubarb, sugar, and orange juice in a saucepan. Bring to a simmer over medium heat, stirring to dissolve the sugar. Cover and reduce the heat to low. Simmer gently until the rhubarb has softened completely, about 10 minutes. Watch carefully as the mixture wants to boil up and over. Stir in the strawberries and cook uncovered, stirring often, until they soften slightly, about 2 minutes. Puree the mixture in a food processor or blender. Refrigerate, covered, until chilled. Makes about 1 cup.

To make the panna cotta: Put the milk in a small saucepan. With the tip of a paring knife, scrape the vanilla bean seeds into the milk, then add the pod to the milk as well. Bring to a simmer over medium heat. Cover, remove from the heat and let steep for 30 minutes. Remove the vanilla bean pod with a fork.

In another bowl, whisk together the yogurt, sugar, and salt.

Sprinkle the gelatin over the warm milk and let soften for 5 minutes. Return the saucepan to medium heat and bring the milk to a simmer, whisking constantly until the gelatin completely dissolves. Cool 5 minutes, then whisk the milk mixture into the yogurt.

If you prefer to serve from glasses, parfait style: Spoon about 2 tablespoons strawberry-rhubarb sauce in the bottom of each of six 6- to 8-ounce glasses. Divide the yogurt mixture evenly among the glasses. (I put the yogurt mixture in a measuring cup with a pour spout so I can distribute it easily.) Cover the glasses with plastic film and refrigerate until set, at least 3 hours.

If you prefer to serve unmolded on a plate: Lightly grease six 6- to 8-ounce ramekins with vegetable oil. Divide the yogurt mixture among the ramekins. Set the ramekins on a tray and cover with plastic film or another tray. Refrigerate until set, at least 3 hours. To unmold, run a thin knife around the perimeter of each panna cotta. Invert a serving plate on top. Grasping the plate and ramekin with both hands, invert them and give a little shake. The panna cotta should slip out. Spoon 2 tablespoons of strawberry-rhubarb sauce around each panna cotta, garnish with fresh berries and a mint sprig, if desired, and serve immediately.