The Bojon Gourmet

0 Position a rack in the lower third of the oven and preheat to 350º. Grease a 9" springform pan and line the bottom with a round of parchment paper.
1 Spread the nuts on a small baking sheet and toast lightly in the oven until fragrant, about 10 minutes. Let cool completely (spread on a plate and stick in the fridge to speed this up - do not grind hot nuts with the chocolate and sugar or it will melt the chocolate).
2 In a food processor, whizz together the thoroughly cooled nuts, the chocolate, the salt and half of the sugar until finely ground but not powdered. Set aside.
3 In the bowl of a stand mixer fitted with the whisk attachment (or with electric beaters, or with a whisk and your brute strength) beat the egg whites with the cream of tartar on medium-high speed until foamy. Still whipping, slowly add in the remaining 1/2 cup of sugar. Continue whipping until soft peaks form (i.e., when you lift the whisk out and hold it upside-down, a peak will flop over; see photo in post, above). Immediately but gently fold in 1/3 of the chocolate mixture using a large, rubber spatula, until mostly combined. Fold in half the remaining chocolate mixture, then the rest, until incorporated, and no large clumps of either nuts or egg white remain.
4 Spread the batter evenly into the prepared pan. Bake until the torte is puffed, golden brown, and a toothpick inserted comes out clean, or smeared with a bit of melted chocolate, 30 - 35 minutes.
5 Remove from the oven, and let cool completely on a cooling rack. Remove the sides from the pan, and invert the cake onto the rack, remove the parchment, and then re-invert it onto a serving plate.
6 Dust with powdered sugar or cocoa, and serve with whipped cream and chopped pistachios, if desired.