01 - In a small bowl, sprinkle powdered gelatin over cold water. Allow to bloom for 5 minutes until softened.
02 - Combine heavy cream, whole milk, granulated sugar, dark brown sugar, ground ginger, cinnamon, nutmeg, cloves, and salt in a medium saucepan. Heat over medium heat, stirring constantly, until the sugar dissolves and the mixture is steaming but not boiling.
03 - Remove the saucepan from heat. Stir in the bloomed gelatin mixture until it is completely dissolved.
04 - Stir in the vanilla extract until well combined.
05 - Pour the mixture through a fine-mesh sieve into a jug to ensure a silky smooth consistency.
06 - Divide the panna cotta mixture evenly among 6 individual ramekins or dessert glasses.
07 - Allow the panna cotta to cool to room temperature. Cover each ramekin or glass and refrigerate for at least 4 hours, or until firm and set.
08 - To serve, top with whipped cream and crushed gingerbread cookies, if desired.