烤箱预热至160℃，在直径9英寸的蛋糕模内部涂上一层油（黄油或椰子油），并在模具底部垫上油纸。Preheat the oven to 320°F (160°C). Use a spring form, maximum 9 inches (20-22 cm) in diameter. Grease the form with some butter or coconut oil and fasten a piece of round parchment paper to the bottom.
将巧克力掰碎，黄油切小块，一起隔水融化（或用微波炉）。注意融化时要不断搅动。完全融化后放置稍冷却。Break the chocolate into pieces and dice the butter. Melt together using a double boiler or the microwave. Be careful, chocolate can burn so stir often. Let cool a little when melted.
将蛋清蛋黄分离至不同的碗中，蛋白中加入盐，搅拌机打至硬性发泡，备用。Separate the eggs and put the yolks and whites in separate bowls. Add the salt to the egg whites and whisk until stiff peaks form. Set aside.
香草精加入蛋黄打至顺滑。Add the vanilla to the egg yolks and whisk until smooth.
融化的巧克力黄油倒入蛋黄，混合均匀，拌入打发的蛋清，直到蛋清的白色条纹完全消失，不要拌过头。将拌好的蛋糕糊倒入模具中，放入烤箱烤约15分钟。可以用刀插入蛋糕看看是否烤熟了。蛋糕内部应该是湿润的但水分不能过多。Pour the melted chocolate and butter into the egg yolks and mix well. Fold in the egg whites. Keep folding until you can’t see any white streaks from the egg whites but no more than that. Pour the batter into the form and bake for about 15 minutes. Probe with a knife to see when it’s ready. It should be moist, but not runny.
温食/冷食最佳，按个人喜好加浆果或者抹上打发的淡奶油。This cake is best served cold or lukewarm with berries and whipped heavy cream.