Pumpkin Icebox Pie

INGREDIENTS

• 16 cinnamon graham crackers, broken into large pieces
• 1 tablespoon dark-brown sugar
• 1/2 teaspoon coarse salt
• 1/2 cup (1 stick) unsalted butter, melted and cooled
• 3 teaspoons unflavored powdered gelatin (from 2 packets)
• 1 can (29 ounces) pure pumpkin puree
• 4 ounces cream cheese, room temperature
• 1 can (12 ounces) evaporated milk
• 1 cup packed dark-brown sugar
• 3/4 to 1 teaspoon ground cinnamon
• 1/4 teaspoon ground or freshly grated nutmeg, plus more for garnish
• 3/4 teaspoon coarse salt
• 1 cup heavy cream
• 1 tablespoon confectioners' sugar