Preheat oven to 175°C (350°F). Butter and line an 8-inch springform pan or cake pan with parchment paper.
Separate eggs: 4 egg whites in one bowl and 4 yolks plus 2 whole eggs in another.
Melt chocolate: In a heatproof bowl over simmering water, melt chocolate chips and butter, stirring until smooth.
Cool slightly. Whisk egg yolks, whole eggs, and half the sugar in a mixing bowl.
Slowly add in the melted chocolate mixture and whisk until well combined.
Beat egg whites in an electric mixer for 2 minutes until foamy.
Gradually add remaining sugar, continue beating until soft peaks form.
Gently fold in egg whites into the chocolate mixture in batches.
Pour batter into the pan and bake for 35-40 minutes or until the top is cracked and the center is set.
Allow cake to cool completely in the pan, deflating and cracking further.
Whip cream with vanilla and icing sugar until soft peaks form.
Remove cake from the pan, top with whipped cream, cocoa powder, and chocolate shavings. Chill for 1 hour.
Slice and enjoy!