Preheat the oven to 180°C / 350°F / gas 4. Prepare your lined tin.
Place the butter in a heatproof bowl along with the dark chocolate. Place a small amount of boiling water into a saucepan and rest the heatproof bowl with the butter and chocolate on top, then melt the contents on a low heat. You don't want the water to boil. Once melted set aside.
Add your sugar and eggs to an electric mixer and whisk for about 2 minutes until it's nice and frothy.
Pour your chocolate mixture into the egg mixture and whisk for a few minutes until everything is combined.
Sift the flour and and cocoa powder into your mixture and stir with a wooden spoon until you have a nice thick batter and everything is combined.
Add over half of the chocolate chips and cherries, keeping the rest to sprinkle on top. Give the mixture a good stir.
Pour all the mixture evenly into your prepared tin, gently bang the tin on the work surface to get rid of any air bubbles.
Scatter the cherries upright on top and sprinkle on the chocolate chips.
Bake in the oven for 25-30 minutes, make sure you check them with a metal skewer and the mixture is not too moist. They may be a little gooey though due to the moisture of the cherries.
Let the brownies cool down it the tin, once cooled cut up in to squares.