Meatballs with spinach

400 g lean beef, minced
400 g lean pork, minced
8 mushrooms, sliced
100 g spinach, cooked and chopped
2 eggs, beaten
fresh bread crumbs, soaked in milk
milk
flour
fresh parsley, chopped
Spanish extra virgin olive oil
For the sauce:
2 onions, chopped
2 spring onions, chopped
4 cloves garlic, roughly chopped
2 ripe tomatoes, roughly chopped
Spanish extra virgin olive oil
small glass beef stock
salt and freshly ground black pepper

1. In a bowl, mix together the two meats, spinach, egg, bread crumbs and salt. Roll about a tablespoon amount of meat to form a ball, toss in the flour. Do this to form all the meatballs then fry gently until browned.
2. To make the sauce: saute the vegetables in a pot with the oil, adding the stock if they become dry, and salt and pepper. Cook gently from 15 minutes, Now blend in a food processor and return to the pot, carefully adding the meatballs. Stir in the mushroom slices and parsely and cook gently for a further 15 minutes.