Mary Berry Peppermint Slice

Mary Berry’s Peppermint Slice brings together the nostalgic crunch of Marie biscuits, the playful crackle of Rice Bubbles, and the bold freshness of peppermint chocolate, all bound by silky condensed milk and topped with smooth melted chocolate.

Getting the chocolate topping to set without cracking — and keeping the base firm yet chewy — is a small art. Mary Berry’s method quietly teaches you both. This is a true everyday treat, refined by technique.

Why This Works So Well

• Base Structure Matters: Crushing biscuits finely (but not to dust) lets the base bind tightly without becoming a soggy mass.
• Peppermint Chocolate Choice: Using Peppermint Crisp or Aero gives tiny, airy shards that melt differently from solid chocolate, offering that surprising crunch.
• Chocolate Tempering Shortcut: Adding a little vegetable oil softens the set chocolate just enough to slice neatly without fracturing the top.

Key Ingredients for Success

Marie Biscuits
The neutral biscuit backbone. If too coarsely crushed, the base crumbles. If too fine, it turns stodgy.

Peppermint Crisp Chocolate
This isn’t just for flavor; it creates a shatteringly light texture. Substitutes like Aero bars work, but a dark peppermint chocolate would be too dense.

Rice Bubbles (Rice Krispies)
Bring crispness and an airier bite. Leaving them out leads to a heavy, dense slab.

Condensed Milk
Acts as glue and sweetener in one. Don’t swap for evaporated milk — it won’t bind.

Butter
Adds richness and helps set the base firmly when chilled.

Milk Chocolate (for topping)
Melts smoothly and complements the mint. Dark chocolate can overpower the balance; white chocolate can make it overly sweet.

Smart Tweaks That Actually Work

• Dark Chocolate Fans: If you prefer darker flavors, use 70% dark chocolate but stir in an extra tablespoon of condensed milk to soften the bitterness.
• Nutty Version: Add 1/3 cup chopped roasted almonds for extra crunch — but keep total dry mix ratios the same.
• Dairy-Free: Use coconut condensed milk and dairy-free chocolate — but expect a slightly softer set.

Lessons From the Kitchen

What Went Wrong	Why It Happens	How to Fix It
Crumbly Base	Biscuits too coarse or not enough condensed milk	Crush biscuits finer; measure liquids carefully
Chocolate Topping Cracks	Chocolate too hard from fridge	Let sit 10 minutes at room temp before cutting
Slice Won’t Set	Warm kitchen or rushed chilling	Chill overnight for best firmness

Step-by-Step Method (With Expert Tips)

1. Prepare the Tin
Line a 25 x 18 cm slice tin with baking paper, leaving an overhang.

2. Crush the Biscuits
Use a food processor or rolling pin. Aim for a sandy crumb with a few small flecks.

Pro Tip: “Leaving some tiny chunks gives the base bite without making it dry.”

3. Chop the Peppermint Crisp
Use a sharp knife and keep pieces small for even distribution.

4. Mix the Base
Combine crushed biscuits, Rice Bubbles, coconut, and chopped peppermint chocolate. Stir well.

5. Bind the Mixture
Add melted butter and condensed milk. Stir until fully combined and sticky.

6. Press Into Tin
Use the back of a spoon to press firmly and evenly.

Pro Tip: “Press hard enough that it holds shape, but not so hard that Rice Bubbles get crushed.”

7. Melt the Chocolate
Microwave in 30-second bursts at 50% power, stirring each time. Add 1 tbsp oil if you want a softer top.

8. Finish the Slice
Pour melted chocolate over the base. Sprinkle extra crumbled peppermint chocolate while still warm.

9. Chill to Set
Refrigerate for at least 2-3 hours or preferably overnight.

10. Cut and Serve
Dip a sharp knife in hot water, dry, then slice cleanly.

Serving Suggestions and Storage Tips

Serving

• With whipped cream or vanilla ice cream
• Alongside a strong coffee or mint tea

Storage

• Fridge: Airtight container for up to 1 week.
• Freezer: Wrap slices tightly — freeze for up to 2 months.

Reheating

• Microwave: 10-15 seconds for gentle warming.
• Oven: 300°F for 5-8 minutes on a tray.

A Bite of Culinary History

Slices like this gained fame in mid-20th century Britain and Australia, where “traybakes” offered busy cooks a no-oven, crowd-pleasing treat — perfect for community events and bake sales.