In a bowl with a whisk attachment, beat the egg whites well and gradually add the sugar. Continue beating until stiff peaks form. In a separate bowl, whisk the egg yolks and oil, then add the lemon zest. Transfer the yolk mixture to the egg whites and continue whisking on low speed until combined. Gently fold in the flour and baking powder, taking care not to deflate the foam.

Line a baking sheet with parchment paper and brush it with oil. Pour in the batter and spread it evenly. Preheat the oven to 320°F (160°C) and bake for about 12 minutes, or until golden brown (baking times may vary depending on the oven). Carefully release the cake from the parchment paper and flip it onto another sheet of parchment paper.

Spread a thin layer of dulce de leche over the cake, then add 3/4 of the whipped cream and smooth it out. Roll the cake into a log, using the parchment paper to help. Spread the remaining whipped cream over the entire cake, sprinkle with coconut, and decorate with cherries or grated milk chocolate, as you prefer.