In a medium saucepan over low heat, whisk together the egg yolks and sugar. Add the cocoa powder and stir until well combined.

Pour in the whole milk and continue to whisk as it heats up. It’s essential to keep stirring to prevent the eggs from scrambling!

Once the mixture is warm (not boiling!), remove it from the heat. Stir in the heavy cream, chopped dark chocolate, instant espresso powder, and sea salt. Keep stirring until the chocolate has melted completely.

Allow the mixture to cool. Then, transfer it to an airtight container and freeze until solid. This will form the chocolate custard you’ve been dreaming about.

Now that the custard is ready, let’s create the shake.

In a blender, combine ½ cup of whole milk, 1½ cups of your frozen chocolate custard, and ¼ teaspoon of vanilla extract.

Blend until smooth. You want it creamy, with no lumps. If it’s too thick, add a bit more milk and blend again.

Taste it. Feel free to adjust with a bit more vanilla or even a dash of sugar if you prefer it sweeter.

Pour the shake into tall glasses. I recommend using frosted glasses for an ultra-refreshing experience!

Top with whipped cream if you like, and maybe drizzle a little chocolate syrup over the top.