Outrageously easy to make, and the unbaked mixture keeps well in the freezer or fridge. The only stressful point is in cutting the chocolate – last attempt resulted in chocolate bits and pieces all over the kitchen – but it may be one of our scientific experiments gone wild.. So – I never succeeded in cutting the Brazil nuts nor chocolate into chunks small enough to make mini size cookies, but the challenge is on!
The quantities below make 30 regular-sized cookies. This set is good enough for the large flat cookie sheet
• 125g unsalted butter, softened
• 225g light soft brown sugar
• 1 tsp vanilla extract
• 1 medium egg
• 25g cocoa
• ¾ tsp ground cinnamon
• 175g plain flour
• ½ tsp baking soda
• 200g milk or dark chocolate, chopped roughly into big chunks
• 150g Brazil nuts, cut into quarters
1. Put the butter, sugar and vanilla in a bowl and beat until smooth.
2. Beat in the egg, then stir in the cocoa and cinnamon.
3. Add the flour and soda, work until combined, then mix in the chocolate and nuts; I use my hands because I find it easier to scrunch up the dough and get the mixture really even.
4. Pinch off nuggets of dough the size of a ping-pong ball (for regular cookies) or unshelled hazelnut (for mini ones), and roll between your palms until smooth.
5. Cover a baking tray with nonstick paper and place the soon-to-be cookies on it 3-4cm apart. 
6. Heat the oven to 180C/350F and bake for eight to 10 minutes (for mini cookies) or 12-14 minutes (for regular ones).
7. Leave to cool on the tray for a few minutes, then transfer to a rack with a spatula.
8. Once cold, store in an airtight container.