1. Heat the oven to 180°C, gas mark 4. Line a 20cm square tin with baking parchment.
2. Place the butter and chocolate in a heatproof bowl and melt together in a bowl set over a pan of simmer water or in a microwave. Leave to cool a little.
3. Using an electric whisk, beat together the eggs and sugar until light and fluffy. Beat in the cooled chocolate mixture.
4. Mix the coffee, cocoa, flour and baking powder together then pour into the chocolate mixture and gently stir together. Finally, mix in the pecans then pour into the tin and bake for 25 - 30 minutes until just set but still a little squidgy in the centre. Leave to cool completely in the tin then lift out and cut into squares. Serve with a scoop of vanilla ice cream for pudding or with a cup of Starbucks VIA coffee for a mid-morning or afternoon treat.