Prepare the dough: Combine flour, yeast and water in a bowl and mix well, then add oil and salt and continue to work.
Once you have obtained a smooth and elastic dough, transfer it to a bowl lightly greased with oil, brush with a little oil, cover with cling film and leave to rise for at least 10 hours or until it doubles in size.
When the dough is almost ready, start preparing the other ingredients: cook the hard-boiled eggs (about 8 minutes), then shell them and cut them into slices.
Cut the fior di latte into cubes.
Season the puree with salt, oil and oregano.
Take the dough and roll it out onto a lightly oiled baking tray.
Season with the sauce and cook for about 5-7 minutes in a fan oven preheated to 250°C.
Remove from the oven, add the fior di latte and cook for another 5-7 minutes.
Remove from the oven and season with eggs and mayonnaise.
The Rossini pizza is ready, all you have to do is serve it immediately.