Guava-Grapefruit Possets

Ingredients

• 2 cups heavy cream
• ½ cup (100 g) sugar
• 1 Tbsp. (packed) finely grated grapefruit zest
• ¼ cup fresh grapefruit juice
• ¼ cup fresh lemon juice
• ¼ tsp. kosher salt
• 4 oz. guava paste (preferably Goya or La Fe), cut into small pieces
• 1 tsp. fresh lemon juice
• Flaky sea salt

Steps

1. Bring cream, sugar, and grapefruit zest to a simmer in a large saucepan over medium-high, whisking occasionally, and cook (still whisking from time to time) until sugar is dissolved and cream is reduced by about a quarter (mixture should be just shy of 2 cups), 8–10 minutes.
2. Remove pan from heat; immediately add grapefruit juice, lemon juice, and salt; whisk vigorously just until combined. Strain mixture through a fine-mesh sieve into a large measuring glass or a small bowl or other container with a spout.
3. Pour into 4 glasses, dividing evenly (about ½ cup each) and chill until set, at least 3 hours. Do ahead: Possets can be made 2 days ahead. Cover and keep chilled.
4. Cook guava paste and ¼ cup water in small saucepan over medium, whisking vigorously, until paste is melted and mixture is smooth, about 4 minutes. Remove from heat and add lemon juice, whisking well.
5. Spoon jelly over set possets (about 1½ Tbsp. per portion) and smooth surface with a spoon. Chill until jelly is cool, 10–15 minutes.
6. Just before serving, sprinkle tops of possets with salt. Do ahead: Possets with jelly (but without sea salt) can be made 1 day ahead. Cover and keep chilled.