Amazing chocolate brownies

Amazing chocolate brownies
I have made many brownies over the years, but this recipe, from Good Food, has got to be the best yet. These brownies are soft, gooey, and very chocolaty and have a beautiful sugar crust. The chocolate chunks and marshmallows also add that little extra *something*. YUMM. They are in great demand. Enjoy. :)

Ingredients
• 185g unsalted butter
• 185g best dark chocolate
• 85g plain flour
• 40g cocoa powder
• 50g white chocolate
• 50g milk chocolate
• 3 large eggs
• 275g golden caster sugar
• Mini marshmallows (optional)

Method
1. Turn the oven to 180C/Gas 4. Grease and line a 20cm shallow tin.
2. Cut the butter into smallish cubes and tip into a medium bowl. Break the dark chocolate into small pieces and drop into the bowl. Melt the chocolate and butter together in a bowl over a pan of boiling water or microwave for 2 minutes (if microwaving, watch carefully, and stir midway through and after melting as it is burns easily!). Leave the melted mixture to cool to room temperature.
3. Chop the white and milk chocolate into chunks on a board.
4. Break the eggs into a large bowl and tip in the sugar. With an electric mixer on maximum speed, whisk the eggs and sugar until they look pale and about double its original volume.
5. Pour the cooled chocolate mixture over the eggy mousse, and then gently fold together with a rubber spatula. Do this slowly so you don’t lose all the air from the eggs.
6. Now tip the flour and cocoa powder into a sieve held over a medium bowl, and tap and shake the sieve so they run through together and you get rid of any lumps.
7. Re-sieve in the flour mixture to the chocolate mixture, and then gently fold in this powder until just combined. Finally, stir in the white and milk chocolate chunks until they're dotted throughout, and add the marshmallows if you are using them.
8. Pour the mixture into the prepared tin, scraping every bit out of the bowl with the spatula. Bake for 20-25 minutes, until the top has a shiny, papery crust and the sides are just beginning to come away from the tin. Take out of the oven.
9. Leave the whole thing in the tin until completely cold, then cut into quarters, then cut each quarter into four squares and finally into triangles. Enjoy!