01 -
Preheat oven to 350°F. Grease a 9-inch springform pan or pie plate.
02 -
In a heatproof bowl, melt butter and 2 cups of chocolate chips together until smooth using a double boiler or microwave at 50% power in 30-second intervals. Allow to cool slightly.
03 -
Using an electric mixer, beat eggs, sugar, and vanilla on medium-high speed until light and fluffy, approximately 3 minutes.
04 -
Gradually mix the cooled chocolate mixture into the egg mixture until fully incorporated.
05 -
Gently fold in flour, baking powder, and salt until just combined. Then fold in remaining 1 cup of chocolate chips.
06 -
Pour batter into prepared pan and bake for 40 to 45 minutes until the center is puffed and a tester comes out with moist crumbs. The top will develop a crackly crust.
07 -
Remove from oven and let cool completely before slicing. Drizzle with hot fudge sauce to serve.