Preheat your oven to 350°F (175°C). Grease two round cake pans with oil or butter and dust with flour.

In a clean mixing bowl, combine the egg whites and half of the granulated sugar. Whip until stiff peaks form (3-5 minutes).

In another bowl, whisk together the egg yolks and the remaining sugar until pale and creamy. Add the vegetable oil and mix.

Gently sift the all-purpose flour into the yolk mixture, folding it in carefully.

Fold the whipped egg whites into the yolk mixture in thirds, being gentle to retain volume.

Pour the batter evenly into the prepared pans. Bake for 25-30 minutes, or until a toothpick comes out clean.

Cool the cakes in pans for 10 minutes before transferring to wire racks. Allow to cool completely.

Prepare mango simple syrup by cooking mango with water until softened (5-7 minutes), then strain.

In a chilled bowl, whip the heavy cream and vanilla until stiff peaks form (2-3 minutes).

Assemble the cake by layering cake, mango syrup, whipped cream, and mango pulp, repeating this process.

Frost the cake with remaining whipped cream and decorate with sliced mangoes.

Refrigerate for 1 hour before serving to set layers and flavors.