01 -
Preheat the oven to 175°C. Grease a 23 cm pie plate or a 23 cm springform pan.
02 -
In a heatproof bowl, melt the butter with 340 g of chocolate chips using a double boiler or microwave at 50% power in 30-second intervals until smooth. Allow the mixture to cool slightly.
03 -
In a stand mixer, beat the eggs, sugar, and vanilla extract on medium-high speed for about 3 minutes until the mixture is pale and fluffy.
04 -
Add the cooled chocolate mixture to the whipped eggs and sugar, mixing until just incorporated.
05 -
Fold in the flour, baking powder, and salt until just blended. Gently mix in the remaining 170 g chocolate chips.
06 -
Pour the batter into the prepared pan. Bake for 35 to 40 minutes, until the centre is puffed and the top may appear cracked.
07 -
Remove from oven and let cool completely in the pan. Slice and serve topped with hot fudge if desired.