Sift the flour and baking powder into a bowl. Add the granulated sugar and cold butter cut into pieces. Mix with your hands until the mixture is crumbly. Add the two eggs and combine everything. Work the dough just until it comes together to keep the butter from warming up. Wrap the dough in plastic wrap and refrigerate for 1 1/2 hours. Meanwhile, peel the nectarines, cut them in half, and remove the pits.

Remove the dough from the fridge, divide it in half, and use the first half while keeping the other half in the fridge. Roll out the dough on a floured surface and place it in a greased springform pan. Cover the base with amaretti cookies, placing them side by side without overlapping.

Arrange the nectarine halves on top of the amaretti, close together. Now, take the remaining dough from the fridge, place it on a sheet of parchment paper, dust with flour, and roll it out. This will help you create a perfect top layer. Flip the parchment over the nectarines and adjust the edges. Bake at 350°F (180°C) for about 40 minutes. Once baked, remove from the oven and dust with powdered sugar.

TIP: While waiting for the oven to preheat, put the crostata back in the fridge, covered with plastic wrap over the entire surface. I usually use a rubber band to keep the wrap in place so the cold air doesn't hit the dough directly. This helps seal the edges well.