Melt the Chocolate : In a small bowl, microwave the dark chocolate in 20-second intervals, stirring between each, until it is fully melted and smooth. Set aside to cool slightly for a few minutes.
Prepare the Base : While the chocolate cools, combine the pitted Medjool dates and the coconut milk in the canister of your high-powered blender. Blend on high for 30 seconds to break down the dates into a coarse paste.
Combine Key Ingredients : Add the avocado flesh, agave nectar, and vanilla extract to the blender with the date mixture. Secure the lid and start blending on a low speed, gradually increasing to medium.
Incorporate the Dry Goods : Pause the blender and add the cacao powder, instant espresso powder, and sea salt. Place the lid back on and blend again, starting on low to prevent the powder from puffing up, then increasing to high until smooth.
Emulsify the Pudding : With the blender running on a medium-low speed, carefully stream the slightly cooled, melted dark chocolate into the mixture. Continue blending until the chocolate is fully incorporated and the pudding is thick and glossy.
The Final Blend : Stop the blender and scrape down the sides with a spatula. Give it one final 30-second blend on high speed to ensure the texture is completely silky and homogenous, with no visible flecks of avocado.
Chill and Serve : Divide the pudding evenly among six small serving glasses or ramekins. Transfer to the refrigerator to chill and firm up for at least 1 hour. Before serving, top with an optional garnish of cacao nibs or fresh berries.