Preheat oven to 400F, and line two baking sheets with parchment or silicone liners.

In a small nonstick saucepan, over high heat, bring the water, butter, sugar, and salt to a boil.

Once it's boiling, immediately remove from heat and stir in flour (all at once!) with a wooden spoon. Keep stirring until mixture pulls away from the sides and forms a ball around the spoon, about 30 seconds. Let rest and cool for about 2 minutes.

Add eggs one at a time, mixing vigorously until incorporated, until batter comes together.

Using a greased tablespoon or small greased cookie scoop, drop rounded spoonfuls about 1-2 inches apart on prepared baking sheets. I usually aim for 12 per pan.

Bake for 10 minutes, then lower the oven to 350F, and bake for 10-12 more minutes, switching the baking sheets halfway through cooking. Let cool on wire racks to ensure crispy puffs.

While they cool, prepare the chocolate sauce.

Stir together the sugar and cocoa in a small saucepan. Stir in the heavy cream and the butter, and bring to a boil, stirring constantly, over medium heat. After 30 seconds, remove from heat, and add in vanilla and salt. Set aside until ready to use.

Once the puffs have completely cooled, cut in half and fill with a small scoop of ice cream. Either stack on a large serving platter, or divide evenly between individual plates, and drizzle generously with hot fudge sauce.