Chocolate Pavé

"So, what exactly is this?" my sister asked, munching on a slice of chocolate pavé.
"I'm not really sure. It's chocolate pavé," I reply.
"Is it cake or something?" she persists.
"I don't know! I guess so," I hesitate.
Chocolate Pavé. Decadent, creamy and smooth. Your ticket to chocolate heaven. I don't know what to classify this under, but it is really good.

 Chocolate Pavé recipe, adapted from Ready for Dessert by David Lebovitz
Ingredients:
115g unsweetened chocolate, chopped
115g bittersweet chocolate, chopped
227g unsalted butter
6 eggs, separated
200g sugar
A pinch of salt
Icing sugar, for dusting the cake
Melted bittersweet chocolate, for decorating the cake

Method:
1.  Preheat the oven to 350F/175C. Butter the bottom and sides of a 9-inch square cake pan, dust it with a bit of cocoa powder, then tap out any excess. Line the bottom of the pan with parchment paper.
2. In a large heatproof bowl, melt butter and both chocolates over a pan of simmering water, stirring occasionally until the mixture is melted and smooth. Remove the bowl from heat.
3. In a stand mixer fitted with the whip attachment(I used my handheld mixer), whisk egg yolks and 100g sugar on high speed until ribbon stage, about 5 minutes. Fold in melted chocolate mixture until well incorporated.
4. In a clean, dry bowl with a clean whip attachment, whisk the egg whites and salt on low speed until they form soft, wet peaks. Gradually beat in the remaining 100g sugar and continue whisking at high speed until stiff peaks form. Fold the egg whites into the chocolate mixture until there are no visible streaks of egg whites. Do not overfold.
5. Scrape batter into the prepared cake pan and smooth the top. Bake until barely set in the middle, about 35 minutes. The cake will rise as it bakes and form a slightly crackly top. Let cool for about 15 minutes.
6. Invert the cake onto a plate, peel off parchment and invert again. Let it cool completely. Dust the top of the cake with icing sugar and cut the cake into squares. Dip a fork in the melted chocolate and wave it back and forth over the cake, creating an abstract design on the top. Serve.