Grease a baking tin and line it fully with parchment paper, including the sides.
Pit the Medjool dates and flatten them with the side of a knife or something heavy. Spread them evenly across the base of the prepared tin, pressing down firmly to compress into a solid, even layer.
Add 2 ½ Tbsp (50g) of the coconut oil and all of the peanut butter to a saucepan over low heat. Mix well and allow to melt gently — don't let it simmer or boil, you only need it melted through. Remove from the heat and let sit for 20 minutes to cool slightly.
Pour the cooled peanut butter mixture over the compressed dates, spreading evenly to cover the surface, then scatter over the roasted peanuts. Chill in the fridge overnight, or freeze for 40–50 minutes, until firm.
Add the dark chocolate and remaining coconut oil to a heatproof bowl and melt over a bain-marie, stirring until smooth. A microwave works too, but a bain-marie gives more even, controlled melting.
Remove the base from the fridge or freezer and pour the melted chocolate over the top, tilting the tin or using a spoon to spread it evenly. Sprinkle with sea salt flakes. Chill for 2 hours or overnight, or freeze for 1 hour, until fully set.
Lift the slice out of the tin and portion with a hot, dry knife for clean cuts.
Chef's Tips
Let the peanut butter mixture cool for the full 20 minutes before pouring it over the dates, as written — pouring it too hot risks softening or shifting the compressed date base instead of sitting neatly on top.Use a bain-marie for the chocolate if you can, as recommended — it melts more gently and evenly than direct heat or a rushed microwave blast, which lowers the risk of the chocolate seizing.Use a hot, dry knife to portion the finished slice — running it under hot water and drying it between cuts gives you clean edges through the set chocolate instead of cracking or dragging.
Storage & Reheating
Refrigerate for up to 2 weeks, or freeze for up to 3 months, in an airtight container. No reheating required — this one's served cold or at room temperature straight from the fridge or freezer.