With the rack in the middle position, preheat the oven to 170 °C (325 °F).
Butter a 8-inch (20-cm) square cake pan and line with parchment paper, letting paper hang over 2 opposite sides. Butter two other sides.
In a bowl, combine the flour, cocoa and salt. Set aside.
In a double-boiler, melt chocolate and butter. Remove bowl from double-boiler. Whisk in the sugar. Add the eggs, one at a time, and beat for 2 minutes. With a wooden spoon, fold in the dry ingredients. Pour the batter in the cake pan and bake for 25 to 30 minutes or until the centre is firm but moist.
Let cool in the pan for approximately 4 hours. Unmould and cut into squares.
Place one brownie piece in a glass cup. Garnish with a small scoop of ice cream and pour steaming espresso coffee on top.
Place one warm brownie piece in a plate and garnish with a scoop of ice cream.