Heat the heavy cream until hot but not boiling.
Add the dark chocolate to the hot cream and stir until fully melted and smooth to create a chocolate ganache.
Pour the ganache into small disc shapes on a parchment-lined tray using mason jar lid rings or silicone molds.
Freeze the ganache discs for at least 15 minutes until firm.
In a large bowl, whisk together the egg yolks, sugar, and melted butter until smooth.
Add the milk and whisk again until combined.
Sift in the flour, baking powder, and salt. Mix until mostly smooth; small lumps are fine.
In a separate bowl, beat the egg whites until stiff peaks form.
Gently fold the whipped egg whites into the batter to keep the pancakes fluffy.
Melt a little butter in a small skillet over low heat.
Add a layer of pancake batter to the skillet.
Place a frozen chocolate ganache disc in the center and gently press it down slightly.
Cover with more batter until the ganache is fully hidden.
Cover the skillet with a lid and cook on low heat for 20–30 minutes until the top is set.
Carefully flip the pancake and cook for another 2 minutes over medium heat.
Serve the Fluffy Chocolate Lava Pancakes warm with maple syrup, berries, butter, or powdered sugar.