Line a square 9-inch x 9-inch (22cm x 22cm) baking tin with parchment paper and set aside.
If using regular-sized or larger marshmallows, cut them in half using scissors or a knife and set aside.
Prepare a double boiler by placing a heat-proof mixing bowl over a medium-sized pot of simmering water.
Break up block of chocolate and place into the bowl over simmering water.
Gently melt over low-medium heat, stirring occasionally until completely melted and smooth.
Once melted, stir through Biscoff spread until well combined and melted through the chocolate. Turn off heat.
Stir through shredded coconut.
Add marshmallows and broken up Biscoff biscuits. Stir until they're completely coated in chocolate.
Spoon into lined tin, spreading out evenly.
Place a few extra Biscoff biscuits, whole or broken up, on top.
Refrigerate for 2-3 hours or until completely set and solid.
Remove from fridge and lift rocky road out from the tin and place on a chopping board. This Biscoff rocky road is softer than regular rocky road so you can cut into straight away and consume it straight away without breaking a tooth!
Take a sharp knife and cut into long slices then into squares.
Serve and enjoy!
Notes
Extra Biscoff biscuits: Leave some extra whole Biscoff biscuits aside to place on top of your rocky road once it's in the tin. Either break them up or leave them whole for a great visual effect.
Slice rocky road with a warm knife: Hold your knife under hot running water from the tap for a few seconds, wipe it dry then cut your rocky road. A warm knife is easier to cut through solid and chilled chocolate.
Store in an airtight container, refrigerated, for up to 2 weeks.
Freeze chopped rocky road in an airtight container with layers of either cling film or parchment paper between the pieces to prevent them from sticking. Freeze for up to 1 month.
Freeze the entire block of the rocky road that's already set after being in the refrigerator by removing it from the tin and wrapping it tightly in a double layer of cling film, leaving it on the parchment paper. Place in an airtight container in the freezer and freeze for up to 1 month.
Thaw frozen rocky road by placing it in the fridge overnight to defrost, still wrapped up and in the container. Then place it on your kitchen counter for several hours until soft enough to eat. Alternatively, thaw it from frozen at room temperature for several hours until soft.