Preheat oven to 180°C. Grease a shallow squared baking tray with the butter and flour. In a large bowl, whisk the sugar and butter until incorporated. Gradually add the eggs yolks into the mixture. Add the flour and keep folding it until you have a light batter. Beat egg whites in a mixer or a whisk until soft peaks form. Fold the egg whites into the batter gently.
Spread a thin layer of the batter into the baking tray. Bake for approximately 4 or 5 minutes. Use your fingers to touch the cake and ensure that it is dry and soft so you can roll it easily.
Place the baked cake in a wet kitchen towel. Spread a thin layer of guava paste and roll it up quickly, with the help of the towel.
Bake another layer of the batter, spread the guava paste and start rolling it where the previous layer ended. Repeat the same process until the last layer. Sprinkle white sugar on top of the cake.
Slice it thinly and gently.