Add the flour with the salt to a large bowl, then add the butter. Coat the stick of butter with flour in the bowl, then using a bench scraper cut the butter lengthwise in half, then lengthwise in quarters, coating each newly cut side in flour. Dice the butter and cover each piece in flour, then with a pastry cutter press the mixture as you would mash potatoes.
Add the ice water little by little and mix quickly with your hands just enough to create a ball of dough. Work the dough as little as possible.
Wrap the ball in plastic wrap and refrigerate for at least one hour.
Meanwhile, make the agretti filling. Collect the cleaned agretti into a pan, add the olive oil and the water, season with salt and cook for about 5-7 minutes, on medium fire, enough to soften the agretti.
Roughly chop the agretti and mix them into the well-drained ricotta. Add also the grated Parmigiano and a good grating of nutmeg. Taste and adjust the seasoning. At the end, mix in two beaten eggs.
Preheat oven to 190°C.
Remove the dough from the fridge, roll it out with some flour and a rolling pin, then line a previously greased and floured 22 cm round pie pan. Fill it with the agretti and ricotta filling, then trim the excess pie crust.
Cut strips from the leftover pie crust and decorate the top of the pan, then brush the pie dough with some milk.
Bake the pie for about 40 minutes, until golden. Serve hot or warm.