Soak the bread in milk for 5 minutes and stir to form a paste.
Add beef, onion, garlic, egg, parsley, salt, and pepper to the bread mixture and mix gently by hand.
Roll the mixture into golf ball-sized meatballs.
Coat the meatballs in flour.
Heat olive oil in a skillet and fry the meatballs until browned, about 10 minutes. Drain on paper towels.
Retain 2 tablespoons of fat in the pan, removing large black bits.
Sauté onions until caramelized, then add garlic and sauté for 1 minute.
Add tomatoes and salt, cook until reduced, about 5 minutes.
Pulse parsley, almonds, and saffron in a processor to make picada.
Add wine and chicken stock to the pan, nestle in meatballs, and add picada. Simmer for 5 to 10 minutes.
Serve meatballs as a tapa with crusty bread or over rice.