A dark chocolate souffle cake is a simple but impressive cake that's guaranteed to please just about everyone. They rise while baking but fall when cooling, and deliver an extra delicious chocolately interior. Flourless and super delicious, all that's needed is a few simple ingredients. 8-10 servings.
Using an electric mixer on high speed, beat the egg whites until frothy. With the mixer running, add the raw cane sugar and continue beating until firm peaks form.
NOTE: Adding an acid to the egg whites while you are beating them helps fluff them up. The acid stabilizes the whites and adds volume. For 4 egg whites I add approximately half a teaspoon lemon juice. If you have it on hand, cream of tartar also works well.
Bake until the top has puffed up and has started to crack, and you see the sides of the cake pulling away from the pan; about 35-40 minutes. Remove from the oven and transfer a wire rack to cool completely in the pan (another 30–45 minutes).
NOTE: the cake will further collapse and may crack a little more as it cools — this can be expected!