How to Make It
Heat the oven to 300ºF. Line an 8- x 12-inch pan with parchment paper. Whisk the egg whites to stiff peaks; then gradually whisk in the sugar and cornstarch, a teaspoon at a time. Spread the mix evenly in the prepared pan. Bake for 1 hour. Cool completely in the pan.
Lay a sheet of parchment paper on the work surface, and sprinkle with sifted confectioners sugar. Turn out the cake onto the paper, and peel off the paper used to line the pan. Spread yogurt over the cake. Scatter the mango, passion fruit pulp, and raspberries.
With one of the short ends of the cake closest to you, lift the parchment paper to carefully roll up into a roulade. Dust with confectioners sugar to serve.