Sift together the flour, cocoa powder, sugar, baking powder and bicarbonate of soda. Stir in half the chilli until everything is combined and a uniform cocoa colour. Set aside.
In a medium bowl, combine the egg yolks, melted butter, buttermilk and the remaining chilli. Stir into the dry ingredients until just combined and you have a thick batter. Whisk the egg whites until thick and forming soft peaks, then fold into the batter in two batches. Resist the urge to stir until all the white has disappeared – a few lumps and streaks are fine as over-mixing will leave you with flat, dense pancakes.
Generously brush a large frying pan with the sunflower oil over a medium-high heat. Reduce the heat to low, then add 3 large individual spoonfuls of batter. Bubbles will start to appear, but don’t flip the pancakes until the bubbles stay open and don’t fill back up with batter. This will take around 3 minutes. Flip the pancakes and cook on the opposite side for 2-3 minutes until golden brown. Transfer to a plate and keep warm while you cook the rest of the batter, adding more sunflower oil if needed. You should have enough for 18 pancakes in total.
When you’re ready to eat, stack three pancakes on to each plate. Serve with the fresh blackberries and a dollop of Greek yogurt.