Preheat your oven to 425°F (220°C). Line a baking sheet with parchment paper.

In a medium saucepan, add water, milk, butter, sugar, and salt. Heat until the butter is melted and the mixture just starts to simmer.

Turn the heat to low. Dump in the flour all at once. Stir fast with a wooden spoon until it forms a dough ball and looks smooth. Keep stirring for about 1 to 2 minutes to dry it out a bit. You’ll see a thin film on the bottom of the pan. That’s a good sign.

Move the dough to a mixing bowl. Let it cool for a couple minutes so it’s not scorching hot. Then add the eggs one at a time, mixing well after each. You want a thick dough that slowly falls from the spoon in a smooth ribbon.

Scoop or pipe small mounds (about 1 to 1 1/2 inches wide) onto the baking sheet. Leave space because they puff.

Bake at 425°F for 10 minutes, then reduce to 375°F (190°C) and bake another 15 to 20 minutes until deep golden and puffed. Do not open the oven door early.

Turn off the oven, crack the door open a little, and let them sit inside for 10 minutes. This helps them dry out and stay crisp.

Cool completely before filling.

Heat the cream and butter until hot but not boiling. Pour over chopped chocolate in a bowl. Let it sit 1 minute, then stir until glossy. Add a pinch of salt. Done.