Preheat the oven to 325 degrees F.
Butter the bottom and sides of a 9-inch springform pan. Line the bottom of the pan with a circle of parchment slightly larger than the bottom of the pan, and butter it as well. Add a pinch of cocoa powder and dust the pan. Wrap the bottom of the pan in 2 or 3 layers of aluminum foil, going pretty far up the sides. This will help keep any water from the water bath from seeping into the pan while baking.
Place a small saucepan of water over medium high heat and bring to a low simmer. Lower heat, and place a glass heatproof bowl on top of the pan, ensuring that the bottom of the bowl is not touching the water. Don't allow the water to boil, keep it at a low simmer. Add the butter and chocolate to the bowl, stirring frequently until both are melted and completely combined. Stir in the coffee and the salt, set aside to cool slightly.
Add the eggs to a separate bowl, whisk them gently to break up the yolks. Then whisk or stir in the sugar until just combined. You don't want to create any froth or volume, you're just bringing the ingredients together.
Gently add the cooled, melted chocolate into the egg mixture in three batches, using a spatula to gently stir them together until combined after each addition.
Place the springform pan into a roasting pan that is larger on all sides. Add warm water to the roasting pan, going up the sides of the springform pan about a third of the way to create a water bath. (Be careful not to spill any water into the torte.) Bake for 50-60 minutes until the center is set and doesn't jiggle. Carefully remove the foil—there may be a bit of water in the layers, so be very careful as both foil and water will be very HOT. Allow the torte to cool completely in the pan, then place it in the freezer for 30 minutes.
Remove from freezer and carefully open the sides of the pan to unmold the torte. Now, here's the part that requires a bit of dexterity. 1. Carefully flip the torte onto a plate so it's top-side down. 2. Lift the edges of the parchment up all the way around, then carefully remove the parchment and the bottom of the springform pan. 3. Place another plate onto the bottom of the torte and flip it so it's right-side up. Allow to sit at room temperature for 15 minutes. Sprinkle with cocoa powder and serve.
Store in the fridge for up to three days, or tightly wrapped in the freezer for up to a month.