Prepare a brownie pan with baking spray or baking paper. I used a 22 x 24 x 5 cm Wilton brownie pan.
Preheat the oven to 350º Fahrenheit.
In a bowl mix the dry ingredients: flour, sugar, cocoa, espresso (optional) and salt.
Melt the chocolate in a bain-marie, to do this we heat water in a saucepan and place a bowl over it, to slowly melt the chocolate with the help of a spatula. We can also melt the chocolate in the microwave, heating it at intervals of 5 seconds and stirring, avoiding burning.
Once the chocolate is melted, add the eggs 1 by 1 and mix with the help of a whisk.
Add the vanilla and mix.
Sift half of the flour and add to the chocolate and egg mixture.
Add the stout or Guinness and mix.
Add the second half of the sifted flour and sugar and mix with a spatula.
Pour into the brownie mold that we have previously prepared.
Bake at 350º Fahrenheit for 25-30 minutes.
Let cool and enjoy our Guinness or stout brownie! Perfect for celebrating Saint Patrick's.