Make the dough: In a bowl (or directly on a clean work surface), combine 00 flour, semolina, and salt. Make a well, add the eggs and olive oil, then mix until a shaggy dough forms. Knead 8–10 minutes until smooth and elastic.
Rest: Wrap the dough tightly and let it rest at room temperature for 30 minutes.
Make the filling: Mix ricotta, spinach, Parmigiano, Pecorino, egg yolk, nutmeg, salt, and pepper until smooth. Refrigerate while you roll the dough.
Roll the pasta: Divide dough into 4 pieces. Working with one piece at a time (keep the rest covered), roll through a pasta machine from the widest setting down to about setting 6–7, dusting lightly as needed, until thin but sturdy.
Portion: Lay a sheet on a lightly floured surface and cut into 4-inch-wide strips.
Fill: Place small spoonfuls of filling about 2 inches apart on one strip. Brush a little water around each mound.
Seal: Lay a second strip over the top. Press around each mound to remove air and seal. Cut into ravioli with a cutter/stamp (or a knife). Crimp edges with a fork if desired.
Hold: Arrange ravioli in a single layer on a floured baking sheet and cover with a towel. Cook right away, refrigerate up to 2 days, or freeze.
Cook: Bring a large pot of well-salted water to a gentle boil. Cook fresh ravioli 3–4 minutes, until they float and the pasta is tender. (From frozen: boil straight from freezer and add 2–3 minutes.)