Pulse cookies in a food processor until coarse. Place in bowl and stir in enough melted butter so that the streusel starts to clump. Spread over parchment lined baking sheet and bake at 350F for 5mins.
Cool completely and spoon into bottom of jars/bowls.
Eggnog Mousse:
Place cream into a bowl with a whisk (or whisk attachment) and place in fridge.*
Sprinkle gelatin over 2 Tbsp cold water and set aside.
Combine milk and eggnog in a bowl or large measuring cup. Place 1 1/2 cups of the milk/eggnog mixture into a pot with the spices & vanilla bean paste. Cook over medium heat, stirring often, until mixture boils.
While the mixture is heating, in a medium bowl, whisk the remaining 1/2 cup of the milk/eggnog mixture with egg the yolks, sugar, and corn starch to form a thick paste.
While whisking vigorously, slowly pour the hot eggnog milk into the egg mixture.
Return mixture to the pot and cook over med-high heat, whisking constantly, until it thickens and comes to a boil.
Take off the heat, stir in gelatin until combined.
Strain into a bowl and place plastic wrap directly on top to prevent a skin from forming. Cool completely (you can use an ice bath to speed the process).
Whip heavy cream until stiff peaks. Pour the cooled egg mixture over the whipped cream and fold in gently.
Pipe into mason jars or pour/scoop into bowls. Place in the fridge to set for 1-2 hours.
Notes
*The colder your cream and utensils are, the better it whips up!