In a saucepan, heat the cream, milk, and sugar. Once the sugar has dissolved, add the salt, vanilla, cacao powder, and espresso powder. Whisk them until smooth, then add the gelatin. Cook for about 3-5 minutes, making sure the gelatin has dissolved.
Next, pour the liquid through a sieve to collect any gelatin pieces that have not dissolved.
Pour the liquid into the silicone mold or containers of your choice. Let cool at room temperature, then transfer to the fridge, and let them firm up for at least 2 hours (if they are smaller in size they'll be ready sooner).
Serve with chocolate sauce or toppings of your choice.
Notes
*You can also use only cream if you don't have milk, just double the amount.