FOR THE CRUST 2 1/4 ounces shelled, unsalted pistachios (1/2 cup) 9 graham crackers 1/4 cup granulated sugar 1/4 teaspoon salt 4 ounces (8 tablespoons) unsalted butter, melted
FOR THE MOUSSE 2 cans (20 ounces each) pineapple chunks, packed in syrup Canned pineapple juice (up to 2 cups), as needed 2 tablespoons plus 2 teaspoons powdered gelatin (from three 1/4-ounce envelopes) 1/2 cup boiling water 2 teaspoons finely grated lemon zest 1/4 cup fresh lemon juice (from 2 lemons) 8 ounces (1 cup) cream cheese, softened 1 cup sour cream 1 1/4 cups confectioners' sugar 2 cups heavy cream Lime Sabayon, for serving
1. Make the crust: Place pistachios in a food processor, and pulse until coarsely chopped. Reserve 1/4 cup, and place in a small bowl. Continue to pulse remaining pistachios until fine crumbs form, and transfer to a large bowl. Pulse graham crackers until large crumbs form (about 1 1/3 cups). Add graham cracker crumbs to pistachios and mix well. Stir in granulated sugar, salt, and butter until well combined. Pat crumb mixture into bottom of an 8-cup, 3- to 4-inch-deep souffle dish. Crust should be about 1 inch thick.
2. Make the mousse: Make a collar for the dish by folding a 24-inch-long piece of parchment into a quadruple-thick strip about 4 inches wide. Wrap very tightly around rim of dish, and secure with tape, making sure there are no gaps between dish and parchment. The collar should come at least 3 inches above the top of dish. Place dish in refrigerator.
3. Drain pineapple in a sieve, reserveing syrup. You will need a scant 4 cups fruit and 2 3/4 cups syrup. (Add enough canned pineapple juice to syrup to reach that amount.) Pulse 1 cup pineapple chunks in a food processor until a coarse puree forms.
4. Place gelatin in a medium bowl. Pour 1 cup pineapple syrup over gelatin, and let stand until softened, about 5 minutes. Pour boiling water over gelatin, and stir until smooth. Stir in lemon zest and juice, and the remaining 1 3/4 cups pineapple syrup.
5. Prepare an ice-water bath. Beat cream cheese with a mixer until soft and smooth, about 3 minutes. Beat in sour cream and 1 cup confectioners' sugar until smooth. Slowly whisk in gelatin mixture until incorporated. Fold in pineapple chunks and puree.
6. Whisk cream with remaining 1/4 cup confectioners' sugar until medium-soft peaks form. Fold into cream cheese mixture. Place bowl in ice-water bath. Stir until slightly thickened, but still pourable, and pineapple chunks no longer fall to the bottom, about 10 minutes. Using a rubber spatula, carefully scrape the bowl while stirring to chill mousse evenly.
7. Place dish on a baking sheet, and pour mousse mixture into the dish, spooning in pineapple chunks. Gently smooth the top. Refrigerate until set, at least 2 hours (or overnight). 8. Sprinkle the mousse with reserved 1/4 cup pistachios. Carefully remove collar from dish. Turn spoonfuls of mousse onto plates and serve with lime sabayon on the side.