Bloom the gelatin for the coffee layer: In a small bowl, sprinkle 1 packet of gelatin over 1/4 cup cold water. Let it sit for 5 minutes until it looks spongy.
Make the coffee mixture: In a saucepan, combine 2 cups hot strong coffee and 1/4 cup sugar. Heat gently until the sugar dissolves.
Take it off the heat and stir in the bloomed gelatin until fully melted.
Set the coffee jelly: Pour the coffee mixture into a shallow dish or divide into serving glasses (filling them halfway if you want layers). Chill in the fridge for 1 to 1.5 hours, until just set. It should jiggle but not stick to your finger.
Bloom the gelatin for the chocolate cream: Sprinkle the second packet of gelatin over 1/4 cup cold milk.
Let it stand for 5 minutes.
Heat the dairy: In a clean saucepan, add the remaining 3/4 cup milk, 1 cup heavy cream, 1/4 to 1/3 cup sugar (to taste), cocoa powder, and a pinch of salt. Whisk over medium-low heat until steaming and smooth, about 3–4 minutes. Do not boil.
Melt the chocolate: Remove from heat and add the chopped chocolate.
Whisk until completely melted and glossy.
Add gelatin and flavor: Stir in the bloomed gelatin and whisk until dissolved. Add vanilla extract. Taste and adjust sweetness if needed.
Cool slightly: Let the chocolate cream cool for 10–15 minutes, stirring occasionally.
You want it warm and pourable, not hot, so it doesn’t melt the coffee jelly layer.
Assemble: If you set the coffee jelly in a large dish, pour the chocolate cream over it to form a second layer. If using glasses, fill to the top with the chocolate cream. To avoid dents, pour over the back of a spoon.
Chill to set: Refrigerate for at least 3 hours, or until both layers are fully set.
Overnight is ideal for clean slices and firm layers.
Garnish and serve: Top with lightly sweetened whipped cream, a dusting of cocoa, and shaved chocolate. For a fun crunch, add chocolate-covered espresso beans.