Grease a 9-inch round cake pan. Set aside.
In a mixing bowl, combine the melted butter with the almond flour, cacao powder, sugar-free sweetener, and a pinch of salt. Mix well and pour into the prepared cake pan.
Refrigerate for 30 minutes until solid and firm.
Next, make the filling: Combine the mashed avocados with the melted chocolate, sugar-free sweetener, cacao powder, almond milk, vanilla, salt, and optionally the rum, using an electric mixer for better results.
With a rubber spatula, spread the mixture on top of the crust.
Garnish with the crumbled peanuts and refrigerate for a minimum of 30 minutes.
Slice and serve cold.