Chilled Pineapple Mousse with Pistachios

Ingredients in this Recipe

1 cup sour cream
1/2 cup boiling water
1/4 cup fresh lemon juice (from 2 lemons)
1/4 cup granulated sugar
1/4 teaspoon salt
2 1/4 ounces shelled, unsalted pistachios (1/2 cup)
2 cans (20 ounces each) pineapple chunks, packed in syrup
2 cups heavy cream
2 tablespoons plus 2 teaspoons powdered gelatin (from three 1/4 ounce envelopes)
2 teaspoons finely grated lemon zest
4 ounces (8 tablespoons) unsalted butter, melted
8 ounces (1 cup) cream cheese, softened
9 graham crackers
Canned pineapple juice (up to 2 cups), as needed
Lime Sabayon, for serving

See Full Recipe at Martha Stewart