Sunken Chocolate Cake - cooking recipe

Ingredients

10 ounces good quality bittersweet chocolate, broken into small pieces (such as Lindt)
5 large eggs, separated
1/2 cup granulated sugar, divided,plus more to sprinkle over baked cake
1/2 cup unsalted butter, at room temperature
1/3 cup very finely ground almonds
2 tablespoons brandy
sweetened whipped cream, as garnish (optional)
fresh berries, as garnish (optional)

Preparation

Set oven rack to lowest possible position in oven.
Preheat oven to 300 degrees F.
Have ready a greased 8-9\" springform pan lined with parchment paper.
Put chocolate pieces into a large microwaveable bowl and cook on HIGH for 1 minute,stir, and continue cooking for 30 seconds, then stir again,repeat as needed until smooth& melted.
Set melted chocolate- still in cooking bowl- over another bowl filled with HOT water on counter.
Meanwhile, beat egg whites,adding just 1/4 cup of the sugar gradually, until stiff peaks form- they will appear shiny.
In another bowl,cream the butter and remaining 1/4 cup sugar until fluffy.
Add egg yolks and beat for 1 minute.
Add finely ground nuts (they should be almost like a gritty powder) and the brandy and beat for 2 more minutes.
Now, your chocolate should still be slightly warm, but no longer burning hot- add just a bit at a time to the butter mixture, stirring with a rubber spatula to combine well until all is added.
Fold just 1/4 of the chocolate butter mixture into the egg whites.
Next, gently pour the now chocolatey egg white mixture into the remaining chocolate butter mixture and fold very gently- you don't want to crush down the egg whites.
(This whole back and forth procedure is essential to keeping the egg whites from getting crushed and to avoid cooking the eggs into scrambled eggs.) Pour carefully into the springform pan.
Bake 40-45 minutes if using an 8\" pan, slightly less for the 9\" pan (about 35-40 minutes).
Cake is ready when a toothpick comes out with thick, moist but NOT wet crumbs stuck to it- it should NOT come out clean.
Let cake cool in pan 30 minutes- the cake will sink considerably.
Remove outer ring of pan and invert cake onto a platter.
-peel off the parchment.
Sprinkle with some additional granulated sugar (or powdered sugar).
This should be served warm, with a dollop of sweetened whipped cream on top, and a garnish of fresh berries in season.
It is moist in texture- more like a fudgey brownie than a fluffy cake texture.
Leftovers should be kept in the fridge.
If you need to make this in advance, set the cake out on the counter about 30 minutes before serving to bring it to room temperature.
Garnish just before serving or the whipped cream will weep and make a mess all over the cake.