Preheat the oven to 190°C and line the tray with baking paper.
Put softened salted butter, light brown muscovado sugar and granulated sugar into a bowl and beat until creamy.
Add in vanilla extract and egg into the butter mixture and mix well.
Sift plain flour, bicarbonate of soda and salt into the bowl and mix.
Add chopped walnuts, iinstant coffee and couverture chocolate chips and mix thoroughly.
Scoop a teaspoon of the mixture and arrange them well apart on the baking tray.
Bake for 8 – 10 mins until they are light brown round the edges and still slightly soft in the middle if you press them.
Leave on the tray for a couple of mins to set before transferring onto a cooling rack.