Preheat oven to gas Mark 4/180°C/160°C fan/350°F. In a bowl, beat the butter substitute and sugar together. Add golden syrup, peanut butter and vanilla extract to the same bowl and mix in well. Add in flour, cocoa and peanuts and mix well, forming a soft sticky cookie dough. Take a spoonful of the mixture, shape into a ball about the size of a walnut and place on a baking sheet lined with baking parchment. Repeat the process until all the mixture has been used, making sure to space them well apart and using more than one baking sheet if necessary. Use the back of a fork to press down and flatten each cookie dough ball. Bake for 12–15 minutes in the oven. Remove and cool on the baking sheet.