Combine the meat, spinach, egg, salt, pepper, nutmeg, and oregano in a bowl. Mix until well blended. Set aside.

Sift the 2 cups flour with the 1/2 tsp salt onto a hard surface. Make a well in the center and add the oil, the eggs and half of the milk. Start mixing the oil, eggs and milk together, gradually blending in the flour and adding more liquid when necessary.

Work the dough until it is smooth and firm - it should be soft but not sticky. Cover with a cloth and let rest for 20 to 30 minutes so it loses any elasticity.

Cut the pasta dough into 2 even pieces and roll paper-thin into rectangular sheets. Put teaspoons of filling on half the strips. Dotting them 2-inches apart. Using a narrow brush, or your fingers, moisten with water a rectangle around each mound of filling. Cover with the other sheet and seal between the mounds of filling by pressing with your thumbs. Cut apart and let dry 2 hours before cooking.

Bring 6 quarts of water to a boil in a large pot. Drop in the ravioli and boil for 5-6 minutes. Stir gently with a wooden spoon to keep them from sticking to one another. Lift them out with a skimmer or strainer and place on a warmed platter. Drizzle tomato sauce over the platter of ravioli.