Prepare all your ingredients for making nut free flourless chocolate cake
Grease and line a 22cm/9in springform pan with butter and baking paper.
Place butter and chocolate in a heatproof bowl over simmering water, ensuring no direct contact. Heat gently.
Melt butter and chocolate until smooth, then cool briefly until lukewarm.
Whisk egg yolks into cooled chocolate-butter mix for your flourless chocolate cake.
Add cocoa, salt, and vanilla; whisk to combine.
Beat egg whites in stand mixer until soft peaks form.
Reduce mixer speed to medium. Gradually add sugar, whisking until glossy, stiff peaks form.
Fold a quarter of the egg whites into the flourless chocolate cake mix, to loosen and make it easier to incorporate the remaining egg whites.
Gently fold remaining egg whites into chocolate until no streaks remain.
Pour nut free flourless chocolate cake batter into the prepared pan, smooth top, and bake until set with a thin crust.
Cool the cake completely in the pan before removing and serving. It will sink, that's normal!
Serve the nut free flourless chocolate cake in thin slices with thick cream or ice cream.