In a medium bowl, add the butter and half of the sugar. Cream together until combined.
Add the cocoa powder, vanilla, and salt and mix until combined.
Whisk in the egg yolks until combined.
Melt the chocolate in the microwave until very runny, then add the chocolate to the mixing bowl. Mix until combined.
Finally, add the almond meal and mix until combined. Set the bowl aside.
In a mixing bowl, add the egg whites and whip on medium (speed 3-4) for 1-2 minutes, or until it gets foamy. Sprinkle in the sugar, and continue whipping the whites.
When all the sugar is added, turn the mixer to medium high (5-6) and whip until medium peaks form, about 2-3 minutes.
Add half the whites to the chocolate batter bowl and fold in the whites with a spatula. Do not mix it to vigorously, you want to keep as much air as possible in the batter.
Add the second half of the whites and fold in to combine.
Line a 6 inch pan with parchment on the bottom. Do not spray or grease the sides of the pan. Pour the batter into the pan and level the top with an offset spatula.
Bake the cake at 350 for 28-30 minutes. To check for doneness, peel a small chunk of the top of the cake back and see if its wet underneath. If not, its done.