Preheat oven to 350°F. Line a baking sheet with parchment paper. Gather all ingredients.
In a small bowl, stir together graham cracker crumbs, salt, butter and vanilla.
Spread mixture onto prepared pan and bake until golden around the edges, 8-10 minutes. Set aside to cool.
In a medium bowl, whisk together sweetened condensed milk, sour cream, pudding mix, lime zest, and lime juice.
Whip heavy cream in the bowl of a stand mixer fitted with the whisk attachment on medium-high speed until soft peaks form, 3-4 minutes.
Gently fold whipped cream into pudding mixture, followed by toasted coconut and mini marshmallows.
Dollop or spread mixture into your desired serving dish. Cover and chill in the refrigerator for at least 30 minutes before serving. Sprinkle with graham cracker mixture and garnish with additional lime zest, if desired.
