Preheat the oven to 350F
Prepare an 8" round springform pan by spraying it with nonstick spray and cutting a round piece of parchment to fit on the bottom the pan. Set aside.
Combine the butter and chocolate in a small pot and place on medium low heat. Heat just until melted and set aside to cool.
In a stand mixer, whisk the egg yolks, vanilla extract, and sugar together until pale in color. Slowly stream in the melted butter and chocolate. Add the almond flour and salt and mix until thoroughly combined.
In another clean mixer, whisk the egg whites on medium speed until it forms stiff peaks. Mix half the egg whites into the batter. The mixture should now be lighter. Gently fold in the rest of the egg whites with a spatula.
Pour the batter into the prepared cake round and bake for 40-45 minutes until a skewer comes out clean.