Preheat the oven to 325F/163C convection and grease and line an 8" square pan with baking spray and parchment paper (leaving an overhang to easily remove them).
Start by brewing the espresso so it has time to cool as you prepare the brownies. Set aside.
120 mL (1/2 cup/4oz) espresso
Place the butter and chocolate in a medium, heat proof bowl and microwave for 1 minute, remove and stir until the chocolate and butter is melted and combined.
170 grams (1 1/2 sticks/3/4 cup) salted butter , 170 grams (1 cup/6oz) dark chocolate (or semi-sweet)
In a large bowl, place the granulated sugar, vanilla and eggs. Whisk them together aggressively for 2-3 minutes, until the mixture is completely smooth.
300 grams (1 1/2 cups) granulated sugar, 3 large eggs, 1 tsp vanilla extract
Add the cocoa powder and whisk until the mixture is completely smooth and combined.
40 grams (1/2 cup) Dutch-process cocoa powder
Add in the melted chocolate and butter and whisk until the mixture is fully combined.
Add in the flour and salt and whisk just until there’s no more streaks of flour left. Spread half of the brownie batter into the prepared pan.
90 grams (3/4 cup) all-purpose flour , 1/2 tsp fine sea salt
Slice the lady fingers into fourths so they're cubed and dip each cube into the espresso for 1-2 seconds (you should have a little less than half of the espresso left over) on each side and place them on top of the brownie batter in the pan.
5-6 store bought lady fingers
Spread the rest of the brownie batter on top of the lady fingers and bake for 40-45 minutes. The top should be thin and crackly and slightly puffed in the enter and the edges should be a little wrinkly.
Tap it against the counter a couple of times, it should deflate a little but not be jiggly at all. When you press on it, it should feel soft underneath but not liquid-y.
Allow to cool in the pan for at least an hour before proceeding with the recipe.
Once the brownies have cooled, use a toothpick or small straw to poke some holes in to the brownies and then brush the top of the brownie with the rest of the espresso.