In a large mixing bowl, add the marshmallows and crushed biscuits, drizzle with the golden syrup, stir until combine.
In a small bowl, add white chocolate and butter, then microwave for 20-30 seconds.
Place the biscoff spread in another small bowl and microwave for 20 seconds until it melts.
Now, pour the melted biscoff spread and the melted chocolate mixture over the crushed biscuits, stir well until combined.
Transfer the mixture into the baking pan, press the mixture firmly into the pan.
Making the topping: In two separate bowls, microwave the biscoff spread and white chocolate until melt.
Then, drizzle over the base then sprinkle the crushed biscuits on the top. Place in the fridge for 2-3 hours, then cut and serve.
Wait a few minutes after the mixture has melted before adding the marshmallows. The marshmallows will melt if the mixture is too hot. It's hardly a tragedy, but it does change the appearance of the rocky road.
Simply replace the butter with plant-based spread and vegan-friendly chocolate and marshmallows to make vegan Biscoff rocky road. Carefully double-check the ingredient list on the packages if you have allergies.
Before you begin, grease the baking pan. Even though this is a no-bake treat, doing so helps hold the parchment in place when putting the rocky road mixture in the pan.
I have noticed that melting the butter, chocolate, and Biscoff spread altogether makes the mixture split into an oily mess. That is something that no one desires! So I highly recommend melting them separately.