Buttermilk Panna Cotta With Rhubarb-Strawberry Jelly

Preparation

1. For panna cotta:

   Step 1

   Place 1/4 cup cold water in a small bowl and sprinkle gelatin over; let stand until softened, about 10 minutes.

   Step 2

   Meanwhile, combine cream, sugar, and salt in a small saucepan; scrape in seeds from vanilla bean and add pod. Bring just to a simmer. Add softened gelatin and stir until dissolved. Remove cream mixture from heat; let cool.

   Step 3

   Remove vanilla pod from cream mixture; discard. Whisk in buttermilk, then crème fraîche. Divide mixture among eight 6-ounce jars, ramekins, or glasses. Chill until set, at least 2 hours.

2. For rhubarb-strawberry jelly:

   Step 4

   Place strawberries, sugar, and 2 1/2 cups rhubarb in a medium heatproof bowl; stir to combine and cover tightly with plastic wrap, crimping plastic wrap just under rim of bowl. Set bowl over a saucepan of simmering water (plastic wrap should not touch saucepan) and cook, without stirring, until mixture looks pale and soft, 40-45 minutes.

   Step 5

   Strain mixture through a fine-mesh sieve into a measuring cup (do not push mixture through or jelly will be cloudy); discard solids. Add water, if needed, so liquid measures 1 cup.

   Step 6

   Place 2 tablespoons cold water in a small bowl and sprinkle gelatin over; let stand until softened, about 10 minutes.

   Step 7

   Meanwhile, bring rhubarb-strawberry liquid to a boil in a small saucepan. Add remaining 1/2 cup rhubarb and cook, stirring occasionally, until tender, about 3 minutes; remove from heat.

   Step 8

   Add softened gelatin to saucepan and stir until dissolved. Let jelly cool completely.

   Step 9

   Top chilled panna cotta with jelly, dividing equally. Cover and chill until jelly is firm, 2-4 hours.

   Step 10

   DO AHEAD: Panna cotta can be made 3 days ahead. Keep chilled.