Step 1: Preheat your oven to 375°F (190°C) and grease an 8-inch springform pan, lining the bottom with parchment paper.
Step 2: In a double boiler or a heat-safe bowl over simmering water, melt the butter and chopped chocolate together until smooth.
Step 3: Remove the chocolate mixture from heat and whisk in the sugar and salt until well combined. Let it cool for 5 minutes.
Step 4: Add the eggs one at a time, whisking well after each addition until the batter is glossy and smooth.
Step 5: Stir in the vanilla extract and sift in the cocoa powder, folding gently until no streaks remain.
Step 6: Pour the batter into the prepared pan and bake for 30-35 minutes, or until a thin crust has formed on top and the center is slightly firm.
Step 7: Cool the torte in the pan for 10 minutes before releasing the sides. Dust with extra cocoa powder before serving.