Preheat oven to 350 degrees F.
Lightly grease two muffin pans. In a food processor or with a rolling pin, finely crush the graham crackers until they’re the texture of sand. Mix well the graham crackers with the cocoa, sugar, cinnamon, vanilla extract and salt. Stir in the warm, melted butter until dark dough is formed.
Press two tablespoons of the ground mixture firmly into each muffin mold.
Beat goat cheese and cream cheese with a hand mixer on low until smooth. Add sugar and the salt; beat until combined. Incorporate eggs one at a time, and then add vanilla. Beat on high until smooth, about 2 minutes.
Pour evenly into muffin molds. Bake for 15 minutes, until set. Cool to room temperature, then refrigerate until cold.
Meanwhile, combine blackberries, raspberries, blueberries, sugar, and water in a pot. Cook over medium heat until berries burst, about 5 minutes. Cool. Refrigerate until using.
Remove cakes from pan, the edges can be loosened with a butter knife by gently moving it around the edge. Spoon berries on top of each cake and garnish with mint leaves, if using.