Preheat your oven to 180°C (350°F) and line a muffin tin with paper liners. Chop the dark chocolate into small, uniform pieces to ensure even melting. Sift the cocoa powder into a small bowl to remove any lumps—this prevents bitter clumps in your final brownie. Measure out all remaining dry ingredients (flour and salt) into another bowl. Ensure your eggs are at room temperature, as they'll incorporate more smoothly into the batter and create a better texture.

Melt the chopped chocolate using either a microwave (in 30-second intervals, stirring between each) or a double boiler over simmering water—avoid getting any water into the chocolate or it will seize. Once melted and smooth, set aside to cool slightly. In a separate bowl, whisk together the melted butter, coffee, brown sugar, and sugar for 3-5 minutes until the mixture becomes light and slightly fluffy. This aerates the batter and helps create a fudgy brownie texture. I like to use freshly brewed espresso or very strong cooled coffee rather than instant—it adds a deeper, more authentic coffee note.

Add the room-temperature eggs to the butter-sugar mixture one at a time, stirring well after each addition to fully incorporate. This gradual approach prevents the batter from breaking and ensures a smooth, homogeneous texture. Pour in the melted chocolate and stir until completely combined and uniform in color. Gently fold in the dry ingredient mixture from Step 1 (flour, salt, and cocoa powder) until just combined—overmixing develops gluten and creates a tough brownie rather than a fudgy one.

Divide the batter evenly among the lined muffin cups, filling each about three-quarters full. Bake for 20-25 minutes at 180°C (350°F) until the tops are set but the centers still have a slight jiggle when you gently shake the tin—this indicates fudgy, moist brownies rather than cakey ones. Remove from the oven and let cool for 2-3 minutes. While still warm, gently press the center of each brownie with the back of a spoon to create a shallow well or cup shape for the tiramisu filling.

While the brownies cool completely to room temperature, prepare the tiramisu topping. In a medium bowl, whisk together the mascarpone and powdered sugar until smooth and well combined—I use Galbani brand mascarpone because it has better texture and moisture content than some other brands. In a separate chilled bowl, whip the cold heavy cream to stiff peaks. Gently fold the whipped cream into the mascarpone mixture along with the vanilla extract, being careful not to deflate the cream. The result should be light, fluffy, and able to hold its shape.

Once the brownie cups have cooled completely, spoon or pipe the tiramisu mascarpone cream from Step 5 generously into the wells of each brownie. For a traditional tiramisu presentation, dust the tops with a light coating of additional cocoa powder just before serving. Serve at room temperature or chilled, depending on your preference—I prefer them slightly chilled as it sets the cream and makes each bite more defined.