Best-ever spaghetti and meatballs

2 tbsp extra-virgin olive oil;

2 onions, finely chopped;

3 cloves garlic, minced;

1 egg;

1⁄2 cup ricotta cheese;

2 tsp fennel seeds, lightly crushed;

11⁄4 tsp salt;

3⁄4 tsp pepper;

1⁄4 tsp each ground cinnamon, cloves and nutmeg;

1 cup coarse fresh bread crumbs;

1⁄4 cup minced fresh parsley;

1⁄4 cup grated Romano or Parmesan cheese;

8 oz lean ground beef;

8 oz lean ground pork;

1⁄2 cup dry red or white wine or chicken stock;

1 can (28 oz) diced tomatoes;

11⁄2 cups crushed canned tomatoes.

1⁄2 cup coarsely chopped fresh basil (or 2 tsp dried);

1⁄4 tsp granulated sugar;

11⁄2 lb spaghetti.

In large nonstick skillet, heat half of the oil over medium heat; fry onions and garlic, stirring occasionally, until onions are golden, 10 to 12 minutes. Scrape into bowl.
In large bowl, whisk together egg, ricotta cheese, fennel seeds, 3⁄4 tsp of the salt, pepper, cinnamon, cloves and nutmeg. Stir in bread crumbs, parsley, Romano cheese and half of the onion mixture. Add beef and pork; combine well. Refrigerate for 30 minutes.
Wetting hands if necessary to prevent sticking, form meat mixture by rounded tablespoonfuls into balls. Add remaining oil to pan. Brown meatballs over medium-high heat, in 2 batches; with slotted spoon, transfer to plate. Pour off fat.
Add wine to pan; bring to boil, stirring and scraping up brown bits. Transfer to Dutch oven. Stir in remaining onion mixture, diced and crushed tomatoes, half of the basil (or all dried, if using), the sugar and remaining salt. Add meatballs. Cover and simmer over low heat, stirring occasionally, for 25 minutes. (Make-ahead: let cool for 30 minutes. Transfer to airtight containers and refrigerate, uncovered, until cold. Cover and refrigerate for up to 3 days or freeze up to 1 month.)
Meanwhile, in large pot of boiling salted water, cook spaghetti until tender but firm, 8 to 10 minutes, drain and return to pot.
Add about 1 cup of the sauce to pasta; toss to coat. Serve with remaining sauce and meatballs spooned over top. Garnish with remaining basil.