Pour the three naturally gluten-free flours into a bowl and mix them with a fork. Add 3g of salt and 5g of sugar to the powders. Cut the butter (cold from the refrigerator) into chunks and work it with the powders to form dough crumbs.
At this point, add a spoonful of water little by little, until you obtain a firm and smooth ball of dough.
Roll out the shortcrust pastry on a sheet of baking paper with a rolling pin, obtaining a disc 3-4mm thick.
Coarsely crumble a dozen extra virgin olive oil Tarallini and sprinkle them all over the shortcrust pastry disc, especially around the perimeter.
Cover with another sheet of baking paper and press lightly with a rolling pin, so that the crumbs stick perfectly to the dough.
Turn the disc upside down, with the side covered in crumbs resting in contact with the pan, and proceed to fill the galette.
Turn on the oven at 200° in static mode.
Spread a generous layer of spreadable cheese on the bottom, leaving 2 or 3 centimeters of edge free from the filling, then cut the cherry tomatoes into slices and distribute them in the center of the shortcrust pastry disc. Crumble the feta and season with extra virgin olive oil, pepper, salt, folding the edge of the galette on itself. On the folded edge, you will see the tarallini crumbs with olive oil which will help to give crunchiness to the rustic pizza.
Bake at 200° in static mode for 35-40 minutes.
Remove from the oven and serve warm.
