Heat the oven to 180C/160C fan/gas 4. Butter the base of a 23cm loose-bottomed cake tin and line with baking parchment. Melt the butter in a small pan over a low heat, then remove from the heat and leave to cool for 3 mins. Whisk the melted butter, oil, yogurt, milk, coffee and eggs together in a large bowl until combined. Whisk the sugar, flour, baking powder and cocoa together in a separate large bowl, breaking up any lumps of sugar with the whisk. Gradually whisk the wet ingredients into the dry until smooth, then pour into the tin. Bake for 55 mins-1 hr until firm to the touch and a skewer inserted into the middle comes out clean with no wet crumbs. Leave to cool completely in the tin.

For the rocky road, tip the biscuits into a food bag and bash with a rolling pin until roughly broken up. Melt the butter, chocolate and golden syrup together in a large pan over a low heat, stirring until smooth. Remove from the heat and leave to cool a little.

Tip the crushed biscuits, mini marshmallows and any extras into the pan and stir until everything is completely coated in the chocolate mixture. Spoon the rocky road over the cooled cake and smooth with a spatula so the top is completely covered. Sprinkle over some extra biscuit pieces, marshmallows and any other bits you’d like to add. Leave to set at room temperature for at least 2 hrs, or chill for 1 hr to help it set more quickly. Remove the cake from the tin, slice and serve. Will keep in an airtight container in a cool place for up to two days.