Prepare Pistachio Filling:
In a food processor, blend pistachios, honey, softened butter, and a pinch of salt until smooth.
Add a bit of milk if needed to create a creamy consistency.
Spoon the filling into small mounds on parchment paper and freeze for at least 30 minutes.
Preheat Oven:
Preheat oven to 425°F (220°C). Grease 4 ramekins with butter and lightly dust with cocoa powder.
Melt Chocolate and Butter:
In a heatproof bowl over simmering water (or in the microwave), melt the dark chocolate and butter together until smooth. Set aside to cool slightly.
Mix Eggs and Sugar:
In a mixing bowl, whisk together eggs, egg yolks, sugar, and salt until thick and pale.
Combine and Fold:
Gently mix the chocolate mixture into the egg mixture.
Sift in the flour and fold just until combined.
Assemble the Cakes:
Fill each ramekin halfway with the batter.
Place a frozen pistachio filling mound in the center of each, then top with remaining batter, covering the filling completely.
Bake:
Bake for 11–13 minutes, until the edges are set but the center is still soft.
Let rest for 1 minute before inverting onto plates.
Serve:
Dust with powdered sugar, sprinkle chopped pistachios, and serve immediately while warm and gooey!