Combine 4 eggs, 2 teaspoons oil and half teaspoon salt in bowl and whisk until well blended. Add flour, a little at a time, beating after each addition. Turn out onto well-floured board and knead several minutes until dough is firm and smooth but not dry. Add more flour if necessary to prevent sticking. Cover and let stand at slightly warm temperature about 30 minutes to ripen. Cut dough in 5 cm portions and roll out slightly to flatten enough to fit into pasta machine. Roll in machine starting with thickest setting and progressing to next to finest setting until pasta is very thin (expansion takes place during cooking). Continue until all dough is rolled into strips. Place strips on floured board and sprinkle lightly with flour. Cut in 10 cm squares and let rest 10 minutes before filling and cooking. Meanwhile, to make sauce, saute onion and garlic in olive oil until golden. Add undrained tomatoes, basil and 2 teaspoons salt. Season with pepper to taste. Bring to boil and simmer 15 minutes. Add sugar at last minute. To make filling, combine ricotta, drained spinach, nutmeg, 4 eggs and Parmesan to taste in bowl and mix well. Season to taste with salt and pepper. Bring large pot of generously salted water to boil. Add 1 tablespoon oil. Drop each piece of pasta into boiling water and cook 3 to 4 minutes, or just until pasta floats to surface. Remove at once and plunge into bowl filled with ice water 1 minute. Drain pasta on clean cloth to prevent sticking. Place 1 tablespoon filling in center of each pasta square. Fold square into triangle, then again into smaller triangle. Press edges to seal. Pour layer of tomato sauce in large baking pan. Arrange cappellacci in rows, slightly overlapping. Cover with remaining sauce and sprinkle with additional Parmesan cheese. Bake at 200ºC 5 to 7 minutes.