Preheat the oven to 180/350/gas 4. Grease a 20cm shallow pan (ideally square, but if using round use a 23cm one)
Break up the chocolate into pieces and melt in a bain marie (or small bowl over a pan of boiling water) along with the butter.
When it is all melted, take off the heat and add the sugar stirring well. You're not trying the dissolve the sugar so don't worry about it looking weirdly grainy.
Sift the flour, baking powder and salt into a bowl, then add in the beaten eggs, walnuts and lastly the chocolate mixture.
Mix well (you can stir it or use a mixer, either way they'll taste just fine, but I got a more even rise with the batch I used the mixer on), pour into the greased pan, level out and bake for 35-40 minutes or until the brownies are pulling away from the side of the tin and they are well risen.
Take them out of the oven and run a knife round the edge of the pan to loosen them, and cut through into 16 squares, but leave them in the tin to cool.
When cold, remove them with a palette knife and store in an air tight tin, or individually wrap them in foil and freeze.
Take one out the freezer the morning you want to use them, and pop in a lunch box where it'll be defrosted by lunchtime.
Amount Per Serving
Calories 162Calories from Fat 72
% Daily Value*
Saturated Fat 3g19%
Vitamin A 145IU3%
Vitamin C 0.1mg0%
* Percent Daily Values are based on a 2000 calorie diet.