Begin by freezing the pistachio paste in individual molds for at least 1 hour.

In a double boiler, melt the dark chocolate and butter together over medium heat, stirring until smooth and glossy.

In a separate bowl, whisk together the eggs and sugar until thick and pale, then fold in the cooled chocolate mixture and sifted flour.

Preheat your oven to 425°F (220°C) and prepare ramekins, coating the bottom with batter, placing a frozen filling in the center, and covering with batter.

Bake the filled ramekins for 12-13 minutes until edges are set and centers are softly jiggly.

Remove from the oven, let sit for 1 minute, then invert onto plates and serve immediately.