For the pasta, sift the flour into a bowl and add the rest of the ingredients, combining to a firm dough, not crumbly or sticky in any way. If it's too crumbly, add a little more wine (or water) but only a bit at a time—just enough to bring it together. Keep kneading, about 10 minutes in total, until the dough is lusciously smooth. Let rest, covered in plastic wrap, for at least 30 minutes.
Roll the dough out to 1-millimeter thick—this means it's quite thin but not so thin that you can see your hand through the other side. If you are using a pasta rolling machine, this is straightforward. If rolling by hand, roll on a floured surface from the center outwards (it's quite an elastic dough).
If you are using a two sided corzetti stamp, first cut out rounds with the concave section. Then, flip the concave side over to reveal the embossed side and place one round of dough there. Place the main embossed design (with the handle) over the top and press firmly. I recommend cutting out then pressing several at a time while keeping the rest of the sheet of dough covered so the dough does not dry out. If using just a one-sided embossed design, you can cut out rounds first and then print your design on the top, pressing firmly. Again, do several at a time and keep the rest of the sheet of dough covered so it doesn't dry out. Place finished corzetti on a clean kitchen towel. You can let them air-dry as they are until they are ready to cook, or you can cook them right away.
Prepare the sauce by blending all of the ingredients except for the cheese together in a food processor or blender. Mix in half of the cheese then set aside. This sauce (much like pesto) can keep well in an air-tight container in the fridge for several days to a week.
Bring a large pot of boiling water to boil. Add a heaped teaspoon of salt. Cook the corzetti in the boiling water until al dente (about 4 minutes—taste one, it should give way gently but have a pleasant bite to it; also check that the pasta should show no signs of white/uncooked flour). Drain, setting aside some (a cup or so) of the cooking water, and then place the pasta immediately back in the pot, over very low heat and add the walnut mixture. Add a splash of the cooking water to loosen. You'll see that as you agitate the pan, tossing the pasta through the sauce and combining it with the pasta cooking water, that the sauce turns into beautiful, glossy, creamy, and off-white. Continue tossing the pasta for 1 minute, adding as much cooking water as needed to loosen the sauce so that it coats the corzetti thickly but smoothly. Serve with the rest of the Parmesan scattered on top (and if you like, a few fresh extra marjoram leaves).
The Australian-Japanese cookbook author has lived in Florence (where a visit to a cheese farm once inspired her to start a food blog) for over 10 years with her Tuscan sommelier husband and two kids. Her third cookbook, Tortellini at Midnight, is out now.