
It’s no secret how much I love a tray bake. They’re some of the easiest recipes to make and everyone has a favourite. One of the most requested tray bakes we get though is Peppermint Slice.
This super simple tray bake is a big favourite with The Boys. Both have recently discovered mint-chocolate ice cream and will always choose a Mint Aero when allowed to pick a sweetie. Taking after their Granny in that department, who has always been a fan of mint Poppets and a box of Bendicks at Christmas.
As far as tray bakes go, this one takes a little bit of time investment, purely because you need to let the layers set in between. But that aside, it’s one that anyone can manage and with a bit of crushed Mint Aero on top, it’s sure to wow anyone who you share it with…that’s if there’s any left to share!

Peppermint Slice
Ingredients
For the Base
- 225 g Digestive Biscuits
- 1 tbsp Caster Sugar
- 115 g Butter
- 3 tbsp Cocoa Powder
- 50 g Dark Chocolate
For the Filling
- 340 g Icing Sugar
- 3-4 tsp Hot Water
- 2-3 tsp American Peppermint Extract
- Green Food Colouring (optional)
For the Topping
- 300 g Dark Chocolate
- Crushed Mint Aero (optional)
Instructions
- Generously grease and line a 28x18cm tray with greaseproof paper and set aside. In a pan, melt the butter, sugar, cocoa and chocolate.
- Meanwhile, crush the disgestive biscuits, either in a sandwich bag with a rolling pin, or blitz in a blender. Add to the melted mixture and stir until combined.
- Transfer the base mixture to your prepared tray and using a wooden spoon, press the mixture into the tray, ensuring you get right into the corners and have an even finish. Place the base into the fridge to chill for 1 hour.
- Once the base has cooled, prepare the filling but sifting the icing sugar into a large bowl. Add 1 tsp of hot water at a time until you have a spreadable consistency; 3-4 tsp of water should be enough but add more or less as required.
- Add the peppermint extract and green food colouring (optional) to the icing and mix until well combined. Spread the icing evenly over the biscuit base and return to the fridge for another 1 hour to set.
- Once the filling has set, remove from the fridge and set aside. Over a bain marie (or in short bursts in the microwave) melt the dark chocolate before pouring and evenly spreading on top of the filling. If desired, top with some crushed Mint Aero.
- Allow the peppermint slice to set in the fridge for at least 1 hour but ideally overnight. Once set, cut into your desired size.

Just made this ,can’t wait to try tomorrow. Love your recipes
Sorry but this didn’t end well, the chocolate set rock hard and pushed all the icing out when I tried to hacksaw it into squares! Too much faffing about for me, I’ll stick to your Tiffin recipe!
I’ve made this quite a few times now, it’s perfect when I remember to cut it an hour after setting the chocolate, but even when I forget it still tastes great!
I’ve made this 4 times now, the same thing happened to me on the second one. I find that chilling for about 3 hours once the icing is on to make sure it’s really well set helps. Once the chocolate topping is on, chill for about 8 minutes, and take it out of the fridge and cut it while the chocolate is still soft, making is easier to cut, then put back in the fridge overnight.
Oh my word!! Fantastic recipe. By far the most delicious mint slice I’ve ever tasted and I MADE IT MYSELF!!! I used half milk chocolate and half dark. I cut it after 2 hours in the fridge (as I couldn’t wait any longer to try it) and it cut well. If I’d have left it over night I think the same would have happened as did with Karen. Will be making this again and again!!
I am from the US but love Scotland and the treats. Please help me know what a digestive biscuit is as I search for a substitute here. Could it be like a graham cracker?
Not 100% sure, but do you get ‘Marie’ biscuits? Digestives are pretty sweet, crumbly biscuits.
Yes, the nearest equivalent is Graham crackers
I made this…went a bit crazy with the cocoa powder, read the recipe wrong and used 50gs instead of a couple of table spoons. Regardless it was lovely and turned out great!!!!
Made lastnight had to add a little extra water for a softer fondant and double cream in the choclate but let’s say this… Simply gorgeous
Surely the water for the icing sugar should be TBSP no TSP?
Agreed!
Can this be frozen ahead of eating?