Cut the butter into tablespoon sizes.
Preheat the oven to 425 degrees.
Line a large baking sheet with parchment paper.
Add the butter, sugar, salt, and water to a deep, heavy saucepan.
Cook over medium high heat until the mixture begins to boil. Immediately remove the pan from the heat once the boiling begins.
Add the flour into the mixture and stir quickly with a wooden spoon or heatproof spatula until complete incorporated.
Return to the heat and stir constantly until the mixture becomes a ball, about 2-3 minutes. It will leave a film in the pan.
Pour the dough into a bowl and let it cool slightly for about 3 minutes.
Make sure the four eggs are nearby. You will add them one at a time.
Add each egg, one at a time. Stir one egg until completely combined before adding the next egg.
When all of the eggs are mixed in, place the dough in a piping bag with a round tip. You can use a Ziploc with the corner cut off if necessary, but it won't be as neat.
Squeeze out the dough in a circle. I made mine in a spiral, but you can also just push the dough straight out. You can make them as large as you would like. Mine were about 1 inch in diameter.
Wet your finger and
Bake the pastry at 425 degrees until it starts to puff up and become golden, about 10 minutes.
Lower the temperature to 375 degrees and bake until fully puffed and golden, about 30 minutes.
Let the pastry cool completely before filling it.
Make the chocolate ganache.
Chop the chocolate and put it in a heatproof bowl.
Heat the heavy cream in a heavy saucepan over medium high heat. DO NOT LET IT BOIL. The cream is ready when steam rises from the surface and small bubbles appear around the edges.
Pour the hot cream over the chopped chocolate and let it sit.
The cream will begin to melt the chocolate. When it all starts to look melty - about 3 minutes - stir it all together with a wooden spoon or heatproof spatula.
Make sure all of the chocolate is combined.
Assemble your dessert by cutting the pastry horizontally. Fill with about 2 tbsp of ice cream. Place the top part of the pate à choux you cut on top like a cap. Drizzle with the chocolate ganache.