Preheat the oven to 160°C fan / 350°F. Line an 8 x 8” / 20 x 20 cm baking tin or 900g / 1 lb loaf tin with baking parchment.
Add the buckwheat and pumpkin seeds to a baking tray and roast for 10–12 minutes until golden. Remove from the oven and set aside to cool.
Melt the chocolate and coconut oil in a bain-marie, or in a heatproof bowl in the microwave on a low heat setting. Stir until smooth, then set aside.
Add the dates, almond butter and a pinch of flaky sea salt (if using) to a food processor. Blend for a few minutes until a coarse paste forms. Add the raisins, melted chocolate, roasted buckwheat and pumpkin seeds. Pulse briefly until just combined.
Transfer the mixture to the lined tin and press down firmly into a smooth, even layer. Chill in the fridge for at least 2 hours, until firm, the slice into bites.
