Add the sugar to a pan over medium heat and cook until melted and amber brown. Pour the caramel into a heatproof bowl and swirl to coat the bottom and sides evenly. Set aside to cool.
Carefully separate the egg whites from the yolks. Whisk the egg whites on medium-low speed until foamy, about 2 minutes. Gradually add the sugar and beat on medium-high until stiff peaks form, about 4 minutes.
Spoon the meringue into the caramel-coated bowl and smooth the surface.
Place the bowl in a baking tray and pour hot water halfway up the sides. Bake in a preheated oven at 300ºF (150ºC) for 35 minutes.
Let the cake cool to room temperature, then refrigerate until fully set.
Run a knife around the edges and flip onto a plate to release.
Notes
Separate Carefully: I always take my time when separating the eggs; just one drop of yolk can ruin the meringue.Whip Until Stiff: I like to beat the egg whites until they form firm, glossy peaks that don’t move when I lift the beaters.Use a Deep Bowl: I find that a tall glass bowl works best for holding the shape and gives a beautiful presentation.Let It Chill Fully: I always refrigerate the cake for at least a few hours; it sets better and tastes even smoother.Flip with Confidence: I do one quick motion when unmolding, then wait a few seconds; the caramel usually releases on its own.