Preheat oven to 165°C/150° Fan/330°F
Grease and line a 23cm square baking tin
In a double boiler, melt the dark chocolate and butter. Put aside
In a large bowl and using a balloon whisk, combine the sugars, eggs and vanilla
Add the chocolate and butter into the mixture
Sift the flour and baking powder over the mixture, then add the chopped pretzels and milk chocolate chips
Gently fold this through until JUST combined (a few spots of flour is ok)
Pour mixture into prepared pan and top with the 16 pretzels (one for each serve)
Bake for 25 mins. Brownies can be a little gooey in the centre still. Don't overcook
Allow to cool in the pan, before cutting into 16 squares°